A homosexual man who has prominent, well-developed muscles.
Example sentencesExamples
So, chaps who overtly dress to accentuate a bit of their bodies look sad and weird, like muscle Marys in cap-sleeved T-shirts.
His backing troupe were a mix of 15 muscle Marys and massively befeathered Argentinean samba dancers.
The last one was a smashing success, with all performers chomping at the bit to do it again, and, barring the occasional horrified muscle Mary, the crowd is supportive and enthusiastic.