A merkin in the gay and lesbian set in Hollywood refers to a "usually" straight male escorting a gay woman to public events so as to attempt to camouflage the lesbian's secret sapphic lifestyle.
"T", the (secretly gay) actress is photogrpahed at the red carpet premiere holding onto "J", a well-known straight actor. People think they're "dating". He's her MERKIN for the evening.
Literally, a pubic wig. But on Usenet and other Net forums, a derisive UK and Commonwealth term for an American, caricaturing the pronunciation of "American" in some US English dialects. Plural sometimes given as "Merkinz".
UK user: "'Zucchini'? You Merkins can't get anything right, it's 'courgettes'."
US user: "Well, if we weren't around, who could you Brits possibly feel superior to?"
In military terms, most especially the Navy, merkin is pubic hair left behind on either a toilet seat, or the rim of a men's urinal. More closely associated to women's restrooms than to men's, but applies to both.
A source of great consternation for those assigned the task of 'cleaning the head(restroom)'.
Jay - "Dude, check out all this fucking merkin on the shitter seat!"
Bob - "Thats foul bro! I aint cleaning that up... its your turn!"