The Vietnamese word "ám muội" is an adjective that describes something that is shady, dubious, underhand, or sinister. It often refers to actions or situations that are secretive or not transparent, implying a lack of honesty or moral integrity.
In summary, "ám muội" is a versatile word used to describe shady or dubious actions or situations. Remember to use it in contexts where there is a sense of suspicion or lack of transparency.