Brownie fairly short of cash (5)
I believe the answer is:
fairy
'brownie' is the definition.
(thesaurus)
'fairly short of cash' is the wordplay.
'short of' suggests deleting specific letters.
'cash' becomes 'l' (The pound sterling symbol is an elaborate L).
'fairly' with 'l' taken away is 'FAIRY'.
(Other definitions for fairy that I've seen before include "eg Puck" , "- Cake, - godmother" , "Sprite with a toadstool for a home" , "Cobweb, perhaps" , "Tinker Bell was one" .)