Former heel and wrist confusion (9)
I believe the answer is:
erstwhile
'former' is the definition.
(I know that former can be written as erstwhile)
'heel and wrist confusion' is the wordplay.
'and' says to put letters next to each other.
'confusion' indicates an anagram.
'heel' put after 'wrist' is 'wristheel'.
'wristheel' is an anagram of 'ERSTWHILE'.
(Other definitions for erstwhile that I've seen before include "Formerly" , "Quondam" , "Former - list where (anag)" , "In the past" , "Former, previous" .)