The Collaborative International Dictionary of English v.0.48:
Rowdy \Row"dy\, n.; pl. Rowdies. [From Rout, or Row a brawl.] One who engages in rows, or noisy quarrels; a ruffianly fellow. --M. Arnold. [1913 Webster]WordNet (r) 3.0 (2006):
rowdy adj 1: disturbing the public peace; loud and rough; "a raucous party"; "rowdy teenagers" [syn: raucous, rowdy] n 1: a cruel and brutal fellow [syn: bully, tough, hooligan, ruffian, roughneck, rowdy, yob, yobo, yobbo]