/ ˈgɪdi; NAmE / adjective ( gid·dier , gid·di·est )
1.
[ not usually before noun ] feeling that everything is moving and that you are going to fall
SYN dizzy :
When I looked down from the top floor, I felt giddy.
2.
[ not usually before noun ] giddy (with sth) so happy and excited that you cannot behave normally :
She was giddy with happiness.
3.
[ usually before noun ] making you feel as if you were about to fall :
The kids were pushing the roundabout at a giddy speed.
( figurative )
the giddy heights of success
4.
( old-fashioned ) ( of people ) not serious
SYN silly :
Isabel's giddy young sister
► gid·di·ly / ˈgɪdɪli; NAmE / adverb :
She swayed giddily across the dance floor.
► gid·di·ness / ˈgɪdinəs; NAmE / noun [ U ]:
Symptoms include nausea and giddiness.
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WORD ORIGIN
Old English gidig insane , literally possessed by a god, from the base of God . Current senses date from late Middle English .