Green’s Dictionary of Slang

1. (Aus./US) a dull, tedious, socially inept and otherwise distasteful person.

1968		‘Hy Lit’ Hy Lit’s Unbelievable Dict. of Hip Words 51: melvin – Handle for a square person who is puttin’ the drag on.
1986		Eble Campus Sl. Fall 4: merv – loser; a spindly, underweight person who appears to study a lot.
1987		N.Y. Times 12 Apr. n.p.: When ‘nerds’ travel in pairs they are referred to as ‘Elroy and Melvin’ [R].
1997		L. Davies Candy 96: I parted my hair at the side [...] I combed it back and stood there looking like just the right kind of Mervin.
2002		‘Valley Girls’ on Paranoiafanzine 🌐 Okay, like, this guy isn’t a total double-bagger, but, like, he’s not a fox at all. I mean, just look at him, he’s like, a total Melvin.

2. a condition in which clothing gets stuck between the buttocks; thus give someone a melvin, to tug someone’s underwear up suddenly and roughly; have a melvin/have melvins/have a murphy, to receive this [seen as a typical problem for sense 1 above].

1989		P. Munro Sl. U. 92: give (someone) a melvin to yank (someone’s) underwear up abruptly or roughly.
1991		J. Algeo Fifty Years Among the New Words (1993) 241: 1990 Fall. Wedgy appears to be a term for a high-school prank [...] Connie Eble reports the synonyms melvin and murphy.
1992		D. Burke Street Talk 2.
2001		OnLine Dict. of Playground Sl. 🌐 Melvin n. v. A reverse wedgie. Pulling the frontside of someones underwear as high as possible, or until he screams and cries in pain. Usually given to wiseass kids who taunt older classmates. Can be especially painful if the person getting the melvin is wearing boxer shorts.