Wife using a single pin that's enormous (8)
I believe the answer is:
whopping
'enormous' is the definition.
(I've seen this before)
'wife using a single pin' is the wordplay.
'wife' becomes 'w' (abbreviation).
'using a single pin' becomes 'hopping' (pins can mean someone's legs).
'w'+'hopping'='WHOPPING'
'that's' acts as a link.
(Other definitions for whopping that I've seen before include "Very large" , "Enormous" , "Huge" , "Gigantic" .)