Insert implement in cut (8)
I believe the answer is:
'insert' is the definition.
(I know that shoehorn is a kind of insert)
'implement in cut' is the wordplay.
'implement' becomes 'hoe' (hoe is a kind of implement).
'in' is an insertion indicator.
'cut' becomes 'shorn' (synonyms).
'hoe' placed within 'shorn' is 'SHOEHORN'.
(Other definitions for shoehorn that I've seen before include "A fitting device" , "It facilitates getting foot into footwear" , "What wife too big for her boots may need" , "Force (in Oxford?)" , "Aid to squeezing foot into footwear" .)