Three-quarters of a shilling (9)
I believe the answer is:
ninepence
'three-quarters of a shilling' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for ninepence that I've seen before include "Three-quarters of a shilling" , "in a right old state" , "amount of old money" , "Using old money, had one over the eight" .)