"I hate it" (3)
I believe the answer is:
ugh
'i hate it' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ugh that I've seen before include "That's disgusting!" , "Exclamation of disgust (3)" , "It's nasty" , "Yuck (colloq.)" , "I'm disgusted!" .)