Source : WordNet®

lightheaded
     adj 1: weak and likely to lose consciousness; "suddenly felt faint
            from the pain"; "was sick and faint from hunger";
            "felt light in the head"; "a swooning fit";
            "light-headed with wine"; "light-headed from lack of
            sleep" [syn: {faint}, {light}, {swooning}, {light-headed}]
     2: lacking seriousness; given to frivolity; "a dizzy blonde";
        "light-headed teenagers"; "silly giggles" [syn: {airheaded},
         {dizzy}, {empty-headed}, {featherbrained}, {giddy}, {light-headed},
         {silly}]