People who pretend to believe or follow rules that they don't actually believe in or follow themselves.
From Greek 'hypokrites' (hypo- 'under' + krinein 'to judge or separate'), literally 'one who judges from below.' Originally meant actors in ancient Greek theater who wore masks and played characters.
The word started as just 'actor' in Greek because actors wore masks and pretended to be characters—so calling someone a hypocrite is basically calling them a bad actor in the play of life, failing to be genuine.
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