Webster's Revised Unabridged Dictionary · 1913

Light-headed

Light-headed (līt"hed`ed) , adjective

1.
Disordered in the head; dizzy; feeling faint; delirious. — Walpole
2.
Thoughtless; heedless; volatile; unsteady; fickle; loose; lacking seriousness; given to frivolity; as, light-headed teenagers.
Light-headed, weak men. — Clarendon