Bugs put up a fight (4)
I believe the answer is:
spat
'a fight' is the definition.
(thesaurus)
'bugs put up' is the wordplay.
'bugs' becomes 'taps' ('tap' can be a synonym of 'bug').
'put up' is a reversal indicator.
'taps' written backwards gives 'SPAT'.
(Other definitions for spat that I've seen before include "Observed" , "Petty row" , "Short gaiter or slight quarrel (4)" , "Pat's involved in squabble" , "Minor argument" .)