masc

Masculine (having qualities stereotypically associated with men; virile).

A person whose gender (identity) is masculine (but who is not necessarily a man).

Then there's trans men and non-binary mascs, who can change their birth certificates to MALE after breast removal surgery. […]

In other words, it's a queer space for all men, and women who are trans. Anyone who is read as a cis woman (e.g., lots of trans men and trans mascs) is not welcomed. Grindr has popularized the terms “discreet,” “straight-passing,” and “convincing” within gay culture.

Abbreviation of Master of Applied Science.