The Oxford Thesaurus An A-Z Dictionary of Synonyms - giddy adj.

1) dizzy, faint, unsteady, light-headed, vertiginous, reeling, Colloq woozy: This medication may make you feel a bit giddy. 2) silly, frivolous, scatterbrained, flighty, capricious, irresponsible, erratic, fickle, volatile, impulsive, reckless, whimsical: You can't marry a giddy young girl like Peggy.