Insincere (adjective) — غير صادق: Not expressing true feelings; false. Below are 8 words with a similar meaning; the linked ones have full GL Dictionary entries with their meaning in Arabic.
Claiming standards or beliefs that one's own behaviour does not follow.
fakehollowfalsetwo-faceddishonestfeigneddisingenuous
Speaking smoothly but without sincerity or depth.
Not telling the truth.