n. & v.
n. 1 vitreous refuse left after ore has been smelted, dross separated in a fused state in the reduction of ore, clinkers. 2 volcanic scoria. 3 sl. derog. a a prostitute or promiscuous woman. b a worthless or insignificant person.
v. (slagged, slagging) 1 intr. a form slag. b cohere into a mass like slag. 2 tr. (often foll. by off) sl. criticize, insult. slag-heap a hill of refuse from a mine etc. slag-wool = mineral wool. slaggy adj. (slaggier, slaggiest).
[ MLG slagge, perh. f. slagen strike, with ref. to fragments formed by hammering ]