Dizzy and frivolous (5)
I believe the answer is:
giddy
This clue is a double definition.
'dizzy' is the first definition.
('giddy' can be a synonym of 'dizzy')
'frivolous' is the second definition.
('giddy' can be similar in meaning to 'frivolous')
'and' acts as a link.
(Other definitions for giddy that I've seen before include "Dizzy or frivoloous" , "Suffering from vertigo" , "Excitable, frivolous" , "Faint - excited" , "Flighty or lightheaded." .)