loon
1. loon \'lu:n\ n [ME loun] 1: IDLER, LOUT chiefly Scot 2a: MISTRESS, HARLOT 2b: BOY 3a: a crazy person 3b: SIMPLETON 2. loon n [of Scand origin; akin to ON lo-mr loon - more at LAMENT] : any of several large fish-eating diving birds (genus Gavia) of the northern part of the northern hemisphere