The Collaborative International Dictionary of English v.0.48:
Trews \Trews\, n. pl. Trowsers; especially, those of the Scotch Highlanders. "He wore the trews, or close trowsers, made of tartan." --Sir W. Scott. [1913 Webster]WordNet (r) 3.0 (2006):
trews n 1: tight-fitting trousers; usually of tartan