A fuss relating to an outstanding piece of work? (2-2)

I believe the answer is:
to-do
'a fuss' is the definition.
(I've seen this before)
'relating to an outstanding piece of work?' is the wordplay.
I cannot quite see how this works, but
'to' is within the answer.
'of' could be 'o' and 'o' is found within the answer.
A single letter 'd' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for to-do that I've seen before include "Fuss and bother" , "Quarrel" , "Bustle" , "Flap" , "Fuss or commotion" .)