a. 1. Disordered in the head; dizzy; feeling faint; delirious. [ wns=1 ] Walpole. Syn. -- faint, swooning, lightheaded. [ 1913 Webster + WordNet 1.5 ]
2. Thoughtless; heedless; volatile; unsteady; fickle; loose; lacking seriousness; given to frivolity; as, light-headed teenagers. [ wns=2 ] “Light-headed, weak men.” Clarendon. Syn. -- airheaded, dizzy, empty-headed, featherbrained, giddy, lightheaded, silly. [ 1913 Webster + WordNet 1.5 ]
-- Light"-head`ed*ness, n. [1913 Webster]
a. Free from grief or anxiety; gay; cheerful; merry. -- Light"-heart`ed*ly, adv. -- Light"-heart`ed*ness, n. [ 1913 Webster ]