Hints about what someone showing contempt might do (4)
I believe the answer is:
spit
'what someone showing contempt might do' is the definition.
'hints about' is the wordplay.
'hints' becomes 'tips' ('tip' can be a synonym of 'hint').
'about' says the letters should be written in reverse.
'tips' in reverse letter order is 'SPIT'.
(Other definitions for spit that I've seen before include "Eject saliva - roasting rod" , "Skewer on which meat is roasted" , "Long, narrow point" , "Show contempt" , "nearly a foot deep" .)