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1.
An acronym for "straight-acting gay man" -- a man who is a homosexual but has none of the stereotypical effeminate traits.

Good examples of SAGMs would be Jack and Ennis from Brokeback Mountain or Detective Smecker from Boondock Saints.
"SAGM for GM. Enjoys rodeos, mountain climbing, and motorcycles."
by machinenvy January 23, 2010