hello Davrous~
"暧昧" means "ambiguous,equivocal", or "dubious; shady; secret",for example:
1.He takes an ambiguous stand on this matter. 在这个问题上,他的态度暧昧(模糊)。
2.a dubious relationship 暧昧关系
we often use "暧昧" to describe a relationship, "暧昧" can be neutral or negative,it depends,for example:
The couple divorced because of the man's affair/new relationship with another woman.
那对夫妇离婚是由于男方与另一个女人有暧昧关系。
it can be neutral when we use "暧昧" on one special relationship,which is more than friendship but not love,or hasn't developed into one real relationship. it's just like Cynthia said.