A masculine gay guy who would sport big muscles in his body and is quite tough. They have deep voices, prefer the company of other men (they have nothing in common with women) and might be on the bear side, the some of them.
There are more diesel queers than there are effeminate gay men or twinks. It's just that the latter are more outspoken and dramatic, so they'd appear in TV more often. Half of the men you see in the gym are diesel queers.
Whilst these men are NOT gay, diesel queers would usually look & act like them: