Hypocrites are liars, slanderers and dishonest people. A hypocrite is someone who pretends to have certain beliefs or opinions that they do not really have. Hypocritical is behaving in a way that is different from what you claim to believe (Longman dictionary of contemporary English)

In his letter to Timothy a leader of the church during his time, Paul said in 1 Timothy 4:1-4 (NLT) , “Now the Holy Spirit tells us clearly that in the last times some will turn away from the true faith; they will follow deceptive spirits and teachings that come from demons. These people are hypocrites and liars, and their consciences are dead.

“They will say it is wrong to be married and wrong to eat certain foods. But God created those foods to be eaten with thanks by faithful people who know the truth. Since everything God created is good, we should not reject any of it but receive it with thanks. For we know it is made acceptable by the word of God and prayer.

Source: http://citofgod..com.ng/2017/01/who-is-hypocrite.html

Good Question, and a very good answer.
In Nigeria when a person who professes religion does something wrong,we are quick to call him a hypocrite.
Any human can fall, irrespective of his knowledge, Christianity experience or level of moral standing. Not every christian who falls into sin is a hypocrite.
To me hypocrisy is a life,hypocrites live such a life,a deceitful,pretentious and sinful life. They say one thing but do another,they are not saints but chronic sinners, whereas a genuine believer can sin,due to carelessness, and other factors,that doesn't mean he has been pretending all along.
Peter sinned by lieing and denying Jesus,but that doesn't make him a hypocrite. Peter loved Jesus but still fell. Hypocrites on the other hand live a pretentious, deceitful life,they claim morality,preach it to others for gain,respect,fame etc but they do not posses it themselves.