Strong negative reaction to a development (8)
I believe the answer is:
backlash
'strong negative reaction to a development' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for backlash that I've seen before include "Violent reaction to event, like reverse whip" , "Provoked adverse reaction" , "Violent reaction to an event - using whip?" , "Strong negative reaction to a development" , "negative comments?" .)