A female who has highly defined biceps likened to that of males. Said female most likely also has a very defined six-pack, more defined than your boyfriend's in fact.

It is often the sign of a lesbian, any woman who practices Wing Chun, or Ms. Universe.
Mike: Man, check out that girl's guyceps!
David: I now know why they call it Manchester.

"Hey, did you see how hot that girl was?"

"Dude, she's tots a lesbo."

"Just cause her name is Leslie---"

"Duuuuude, guyceps. DUH."
by Tigger's Back March 19, 2010
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verb

Another fancier, more acceptable way to say that your masturbating
Jeff: What are you doing later Tom?
Tom: Im working out my guycep later.
Jeff: What gym do you go to?
Tom: My computer chair.
by Jay and Day June 2, 2013
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