Deigns to drop stone? That was an accident! (4)
I believe the answer is:
oops
I'm afraid I can't even guess how this answer relates to the clue.
Can you help me to learn more?
(Other definitions for oops that I've seen before include "I'm sorry" , "Oh dear, I've spilt something!" , "statement after accident" , "Apologetic exclamation" , "Exclamation on making obvious mistake" .)