What car is considerated irreparable?
A vehicle that can be used for parts or scrap only.

If a vehicle is branded as 'junk' or 'irreparable' in error, or importation paperwork indicates it as imported 'for parts', there may be no straightforward means provided in legislation to remedy these errors. These vehicles, if not exported to another jurisdiction with different regulations, will never be registerable or licensed again - even if all needed repairs are made and verified.

It should be noted, however, that such permanent records of damage do not always exist in cases where damaged vehicles retain a clear title. For example, ConsumerReports.org reported that vehicle history checks would at times produce "clean" results despite the vehicles being offered for sale as damaged on such websites as eBay.com and even eRepairables.com, a site specializing in the advertisement of salvage cars for sale

A used car, a pre-owned vehicle, or a secondhand car, is a vehicle that has previously had one or more retail owners. Used cars are sold through a variety of outlets, including franchise and independent car dealers, rental car companies, leasing offices, auctions, and private party sales.

A vehicle history report in the US contains important information about a used vehicle’s past. These reports generally show title records from each state DMV, along with salvage and insurance total loss records and accident records.
http://www.autocheck.com/vehiclehistory/autocheck/en/learn-about-title-brands

Before purchasing a used vehicle, potential buyers often consider the purchase of vehicle history and title reports and salvage check reports to understand a vehicle’s background history. Users are generally interested in whether a vehicle that is being considered for purchase has been in a severe accident, had its odometer rolled back or has lemon history. Sellers of vehicles also check the history of their vehicle prior to listing for sale so they are prepared to answer questions to the condition of the vehicle or history events. Dealers often buy these reports that provide a detailed background on the used vehicle to show their customers. Dealers also run reports prior to acquiring vehicles at auction or from trade-ins to help insure they pay a fair market value. Vehicle prices may be adjusted due to history events on any particular vehicle.

What is it, - lemon history?

Shows if the vehicle has a been reported as a lemon

http://www.autocheck.com/vehiclehistory/autocheck/en/learn-about-title-brands

Insurance total loss information

Shows if the vehicle has been reported as a total loss by an insurance company

http://www.autocheck.com/vehiclehistory/autocheck/en/learn-about-title-brands

Auction history

Lets the buyer know if it has been reported at an auto auction

http://www.autocheck.com/vehiclehistory/autocheck/en/learn-about-title-brands

In Ontario, Canada, new and used vehicle sales are regulated by the Ontario Motor Vehicle Industry Council (OMVIC)

(OMVIC) is responsible for administering Ontario's Motor Vehicle Dealers Act.

http://www.ontario.ca/laws/regulation/080333

What does it mean - clear title?

Has not been branded in this jurisdiction. May be a vehicle which has not been in an accident or has been in an accident minor enough that the cost of repair was less than the cost to write off the vehicle. May also be a vehicle which sustained severe damage in some other jurisdiction (if laws between the two differ significantly) or which was damaged and repaired before the introduction of vehicle branding or was damaged or repaired without notification to an insurance company.

Warranty or service contract availability

Shows whether or not the vehicle has been covered by warranty or service contract

State emission inspection results

Shows the results of a state inspection or emission results as reported by the state

Mileage readings

Lists the odometer readings that have been reported for the vehicle

In North America, vehicle licenses are normally issued by individual provinces and states. Each operates under different regulations.

In some cases, the criteria to define a "total loss" vary - some base the cutoff amount on the nominal value of the vehicle in working condition, others look instead at the value of a working vehicle minus the value of a collision vehicle as scrap, salvage or parts. The percentage of the original value at which the "total loss" label is applied also varies.

http://www.autocheck.com/vehiclehistory/?siteID=0

Odometer malfunctions, such as cables snapping or gears rounding off, also are common in older cars. And in some cases, odometers can actually flip extra miles. All these issues make it difficult to reliably verify the mileage of older cars. That’s why sellers of cars 10 years or older are no longer required to report mileage at the time of sale. On the title under mileage, these cars will be marked “exempt.”

Odometer exempt

For example, if someone purchased a classic Corvette with 70,000 miles and drove it for an additional 110,000 miles, the odometer would only display 80,000 miles instead of the true mileage of 180,000 miles. That’s because the odometer rolled over at 99,999 and re-started again at 0 miles.

A vehicle that has been previously branded as salvage but has been rebuilt/repaired and reinspected. These vehicles are driveable but the rebuilt brand remains on the vehicle's title/registration documents permanently. Some jurisdictions require that rebuilt vehicles imported across provincial or state lines be reinspected before being allowed to retain the rebuilt title.

Odometer fraud, also referred to as "busting miles" (United States) or "clocking" (UK and Ireland), is the illegal practice of rolling back odometers to make it appear that vehicles have lower mileage than they actually do. Odometer fraud occurs when the seller of a vehicle falsely represents the actual mileage of a vehicle to the buyer.

Accident history

Shows if the vehicle has been in a reported accident or has sustained damage

http://www.autocheck.com/vehiclehistory/?siteID=0

Air bag deployment

Shows whether or not the vehicle’s airbag has been reported as deployed

http://www.autocheck.com/vehiclehistory/?siteID=0

Mileage readings

Lists the odometer readings that have been reported for the vehicle

http://www.autocheck.com/vehiclehistory/?siteID=0

Insurance total loss information

Shows if the vehicle has been reported as a total loss by an insurance company

http://www.autocheck.com/vehiclehistory/?siteID=0

Salvage or junk information from titles or other sources

Shows if the vehicle has been reported as a salvage vehicle by a state or has been reported at auction or junk yard

http://www.autocheck.com/vehiclehistory/?siteID=0

A lemon is a (often new) car that is found to be defective only after it has been bought. Any vehicle with numerous, severe issues can be termed so and, by extension, so can any product with flaws too great or severe to serve its purpose.

Today, there are vehicle history services that can help a prospective used car buyer by providing a "history report" based on the vehicle's identification number (VIN). These reports will indicate items of public record, such as vehicle title branding, lemon law buybacks and recalls.

http://www.autocheck.com/vehiclehistory/?siteID=0

Manufacturers have been known to "hide" lemon law buybacks from these reporting services through such unscrupulous methods as holding the buyback vehicle in a dealer's inventory for a short period of time, then funneling it through routine inventory (so-called "dealer only" auctions where the buyback vehicle re-enters the used market as a seemingly legitimate vehicle. While history reports can provide useful information and highlight trouble areas, consumers are still advised to have a trusted, independent mechanic perform a pre-buy inspection on any used vehicle of which they do not personally know the history.

http://www.autocheck.com/vehiclehistory/?siteID=0

A decrepit car is a car that is often old and damaged and is in a barely functional state. Numerous slang terms are used to describe such cars, which vary by country and region, including hoopty, jalopy, shed, clunker, lemon, banger, bomb, beater, rust bucket, voodoo, wreck, or rattletrap.

Age, neglect and damage tend to increase the expense of maintaining a vehicle. The vehicle may reach a point where this expense would be considered to outweigh the value of keeping it. Such vehicles are generally stripped for parts or abandoned

A consumer-protection warning

Cars which have been involved in serious collisions often find their way into auctions and onto dealers' lots. A permanent record of a severe accident warns potential subsequent owners that a car has been damaged (and possibly repaired). Properly repaired and carefully inspected, a vehicle may be acceptable - but an improper repair after a serious accident may leave the vehicle frame, body or key electrical and mechanical systems in damaged or non-roadworthy condition.

In North America, the vast majority of vehicle titles are issued by individual provinces/states and territories. Most have implemented some branding scheme to warn subsequent owners of a vehicle of severe damage to a vehicle due to collision, theft or disaster . The brands and the criteria used to assign them vary widely from one jurisdiction to another.

http://www.autocheck.com/vehiclehistory/autocheck/en/AutoCheck-vehicle-history-reports/c/VHRs

While some vehicles (such as cars exported overseas after severe collision or damaged before the introduction of mandatory branding) may carry no warnings as to their history, others may be branded as "total loss" when they could have been quite repairable in the hands of someone willing to install used parts and do the work at a more modest price.