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1.
To pick up on or sense another’s thought. Usually based on a. knowledge of the person or type of person and context of the situation and b. the ability to read body signals.

The ability to catch on to something without knowing the background.

Entering a conversation midstream and understanding immediately the gist of it.
I knew what he was going to say that, I just sort of “clue in”.
by UWB is really not me February 04, 2010