Fret when drippy folk are in the ascendant (4)
I believe the answer is:
stew
'fret' is the definition.
('stew' can be a synonym of 'fret')
'drippy folk are in the ascendant' is the wordplay.
'drippy folk' becomes 'wets'.
'are in the ascendant' says the letters should be written in reverse.
'wets' backwards is 'STEW'.
'when' is the link.
(Other definitions for stew that I've seen before include "Cook; worry" , "A hole, a fix" , "Tight spot" , "Large watercourse" , "State of mental agitation (informal)" .)