From WordNet (r) 2.0 (August 2003) [wn]:
light-headed
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,
lightheaded]
2: lacking seriousness; given to frivolity; "a dizzy blonde";
"light-headed teenagers"; "silly giggles" [syn:
airheaded, dizzy, empty-headed, featherbrained,
giddy, lightheaded, silly]
From WordNet (r) 2.0 (August 2003) [wn]:
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]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Light-headed \Light"-head`ed\ (l[imac]t"h[e^]d`[e^]d), a.
1. Disordered in the head; dizzy; feeling faint; delirious.
[WordNet sense 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. [WordNet sense 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]