Used to allude to something unsaid or hinted at.

(colloquial) You are familiar with the situation I am describing; used to establish common ground with the interlocutor

A standard defining a standardized isotopic composition of water.

Alternative form of if you know what I mean.

A woman will be more interested in a man if he is not kind to her.

(informal) Treating women badly heightens their romantic/sexual attraction toward you.

Synonym of the road to hell is paved with good intentions