Ointment amount (3)
I believe the answer is:
dab
'ointment amount' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for dab that I've seen before include "[SOMETHING FISHY]" , "Apply light touches of colour to the fish" , "A small fish - bad one" , "Bad kind of fish" , "Gently wipe" .)