Setter's quick to get initial bit of unguent off the cuff (9)
I believe the answer is:
impromptu
'off the cuff' is the definition.
(I've seen this before)
'setter's quick to get initial bit of unguent' is the wordplay.
I cannot quite see how this works, but
'setter's' could be 'im' (referring to the crossword setter) and 'im' is present in the answer.
'quick' could be 'prompt' (synonyms) and 'prompt' is found in the answer.
A single letter 'u' 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 impromptu that I've seen before include "Unscripted" , "Ad hoc: spontaneous-sounding musical piece mastered by Schubert" , "Piano piece" , "On the spur of the moment" , "Extempore" .)