Sentence:  Many if not most of us strive for “it” but few trans women ever get to 100 percent passability. In my experience, there's usually something about us that makes us <WSD>clockable</WSD> on closer inspection. For trans women, this is often our voices. 
Meaning of the word marked with <WSD> tags:  Able to be clocked; possible to clock, that is, to take notice of and recognize (especially as transgender).