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2.
the ability to identify, read, or clock, transsexual and transgender people.
He knew something was different about that girl because she was setting off his transdar.
by ElusiveAppellation June 22, 2011
 
1.
The ability to detect transfolk, especially when the identified person is passing. Generally one tunes in to anatomical cues such as hand structure, brow ridge, adam's apple, and hips.
A: Wow, she is gorgeous. Look at those lips...
B: Look at those hands! Girl is setting off my trans-dar. Are you sure you're ok with that?
A: Why not? She is really something. And besides, I have a few things to learn.
by Kar in Garage May 08, 2007