Two-faced (12)
I believe the answer is:
hypocritical
'two-faced' is the definition.
(similar in meaning)
This is the entire clue.
(Other definitions for hypocritical that I've seen before include "Two-faced" , "Fraudulent" , "pretending to be better than is the case" , "Professing virtues one does not have" , "Insincere" .)