How to translate "暧昧" into English?
Depending on context, 暧昧[pronounced as ài mèi] can take on a few meanings. The following is quoted from Baidu with some explanations in English:


（态度、用意）含糊；不明白。(attitude or intent is unclear or incomprehensible)
（行为）不光明；不可告人。(behavior is dishonorable or secretive, like having an illicit affair)
男女或同性肉体关系还处于想象段。(at the non-physical stage of a relationship, that is, in between friendship and intimate relationship)
男女或同性关系还未发展到恋人关系，但是行为举止和恋人关系差不多。(same as 3)


暧昧 is usually used to describe a kind of ambiguous relationship that is neither here nor there. It is not necessarily a negative word.