曖昧

Adjective

 * 1)  vague; obscure; ambiguous; dubious
 * 2)  intimate but not explicit; showing fondness and interest in a relationship, albeit non-actively; amorous; flirty; flirtatious; having an affair with somebody; adulterous; illicit

Verb

 * 1)  to maintain an ambiguous and flirtatious relationship (with someone)

Etymology
From.

Adjective

 * 1) ambiguous, obscure, unclear, vague

Noun

 * 1) ambiguity, obscurity, opacity