(guilty) of adultery
unfaithful
not honest
lying, untruthful
not loyal (to a person, one's country etc)
unfaithful
outside the regular course of academic work or studies
unfaithful
disloyal
disloyal
(of a person) often changing one's feelings about another person
vacillating, blowing hot and cold
of lie, lie
dishonest
deceitful; faithless
treacherous
false or disloyal (to a friend, cause etc); dangerous, severe
dishonest, disloyal
deceitful(ly)
deceitful
not ethical
dishonest, immoral
not true (to one's duty, a promise etc); committing adultery
disloyal, adulterous
not patriotic
disloyal
without moral principles; dishonest
corrupt