Someone who is two-faced says nice things in front of you, but says bad things about you behind your back.
Someone who acts like your friend in person but speaks badly about you in your absence.
When a person acts a certain way in one place and acts different in another.
1. Brenda seemed so nice on the phone, but acted so different when I saw her yesterday. She is very two-faced.
2. Those girls are two-faced because they only talk to me when they’re in a group.
3. I know Jeff is two-faced because I caught him calling me names as soon as I left the room yesterday.
4. For some people, being two-faced is as easy as chewing a piece of gum.
artful, backstabbing, beguiling, crafty, cunning, deceiving, deceptive, dishonest, double-dealing, foxy, fraudulent, hypocritical, insincere, knavish, lying, misleading, shifty, sly, sneaky, tricky, underhanded, untruthful