Fumbler's word
I believe the answer is:
oops
'fumbler's word' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for oops that I've seen before include "I've messed up" , "statement after accident" , "Apologetic exclamation" , "Exclamation on making a minor mistake" , "Exclamation of making a blunder" .)