Flirt like everybody in extremes of depravity (5)
I believe the answer is:
dally
'flirt' is the definition.
('dally' can be a synonym of 'flirt')
'everybody in extremes of depravity' is the wordplay.
'everybody' becomes 'all' (I've seen this before).
'in' is an insertion indicator.
'extremes of' says to hollow out the word (remove centre letters).
'depravity' with its centre taken out is 'dy'.
'all' put into 'dy' is 'DALLY'.
'like' is the link.
(Other definitions for dally that I've seen before include "Linger" , "Procrastinate" , "Trifle" , "Dawdle - delay" , "Move slowly" .)