1.Definition: having or causing a whirling sensation; liable to falling

"Had a dizzy spell", "A dizzy pinnacle"

Related Adjective(s):giddy, vertiginous, woozy

2.Definition: lacking seriousness; given to frivolity

"A dizzy blonde"

Related Adjective(s):airheaded, featherbrained, giddy, lightheaded, silly