From WordNet (r) 2.0 (August 2003) [wn]:
giddy
adj 1: having or causing a whirling sensation; liable to falling;
"had a dizzy spell"; "a dizzy pinnacle"; "had a
headache and felt giddy"; "a giddy precipice";
"feeling woozy from the blow on his head"; "a
vertiginous climb up the face of the cliff" [syn:
dizzy, woozy, vertiginous]
2: lacking seriousness; given to frivolity; "a dizzy blonde";
"light-headed teenagers"; "silly giggles" [syn:
airheaded, dizzy, empty-headed, featherbrained,
light-headed, lightheaded, silly]
From The Collaborative International Dictionary of English v.0.48 [gcide]:
Giddy \Gid"dy\, a. [Compar. Giddier; superl. Giddiest.] [OE.
gidi mad, silly, AS. gidig, of unknown origin, cf. Norw.
gidda to shake, tremble.]
[1913 Webster]
1. Having in the head a sensation of whirling or reeling
about; having lost the power of preserving the balance of
the body, and therefore wavering and inclined to fall;
lightheaded; dizzy.
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By giddy head and staggering legs betrayed. --Tate.
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2. Promoting or inducing giddiness; as, a giddy height; a
giddy precipice. --Prior.
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Upon the giddy footing of the hatches. --Shak.
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3. Bewildering on account of rapid turning; running round
with celerity; gyratory; whirling.
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The giddy motion of the whirling mill. --Pope.
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4. Characterized by inconstancy; unstable; changeable;
fickle; wild; thoughtless; heedless. "Giddy, foolish
hours." --Rowe. "Giddy chance." --Dryden.
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Young heads are giddy and young hearts are warm.
--Cowper.
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From The Collaborative International Dictionary of English v.0.48 [gcide]:
Giddy \Gid"dy\, v. i.
To reel; to whirl. --Chapman.
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From The Collaborative International Dictionary of English v.0.48 [gcide]:
Giddy \Gid"dy\, v. t.
To make dizzy or unsteady. [Obs.]
[1913 Webster]