You can even describe a person as questionable, if he or she doesn't strike you as completely honest. The original meaning of the word was "that may be interrogated," from the Latin root word quaestionem, "a seeking, inquiry, questioning, or examination."

What is questionable behavior?

adj. 1 (esp. of a person's morality or honesty) admitting of some doubt; dubious. 2 of disputable value or authority.

What does the word questionable?

adjective. of doubtful propriety, honesty, morality, respectability, etc.: questionable activities; in questionable taste. open to question or dispute; doubtful or uncertain: a statement of questionable accuracy. open to question as to being of the nature or value suggested: a questionable privilege.