Commonly used for funds (5)
I believe the answer is:
stock
'funds' is the definition.
(thesaurus)
'commonly used for' is the wordplay.
I cannot quite see how this works, but
'for' could be 'to' (eg both can mean 'in the opinion of') and 'to' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for stock that I've seen before include "Goods in store" , "F < for traditional" , "Neck adornment" , "Farm animals; plant" , "shop's saleable items" .)