From Wiktionary, the free dictionary
Literally, “to be phony like a game chip”.
- IPA(key): /ɛ.tʁə fo kɔ.m‿œ̃ ʒ(ə).tɔ̃/ ~ /e.tʁə fo kɔ.m‿œ̃ ʒ(ə).tɔ̃/
être faux comme un jeton
- (informal, simile) to be phony as a three-dollar bill, to be bent as a nine-bob note, to be extremely dishonest