The Collaborative International Dictionary of English v.0.48:
Giddiness \Gid"di*ness\, n. The quality or state of being giddy. [1913 Webster]WordNet (r) 3.0 (2006):
giddiness n 1: an impulsive scatterbrained manner [syn: giddiness, silliness] 2: a reeling sensation; a feeling that you are about to fall [syn: dizziness, giddiness, lightheadedness, vertigo]