I'm so glad I'm not the only one!
I got 'oops' from 'droops' but then spent absolutely ages trying to work out why, as there was no definition for 'oops', and even 'flops' doesn't really fit as a definition for 'oops'.
I then spent another ages trying to get another word to fit, but couldn't.
It was doing my head in! I've never known a cryptic crossword not give a definition before. Very frustrating.