The Collaborative International Dictionary of English v.0.48:
Laddie \Lad"die\, n. A lad; a male sweetheart. [Scot.] [1913 Webster]WordNet (r) 3.0 (2006):
laddie n 1: a male child (a familiar term of address to a boy) [syn: cub, lad, laddie, sonny, sonny boy]