Scratch rule on clothes initially... (4)
I believe the answer is:
claw
'scratch' is the definition.
(I know that claw is a kind of scratch)
'rule on clothes initially' is the wordplay.
'rule' becomes 'law' (law is a kind of rule).
'on' says to put letters next to each other.
'initially' suggests taking the first letters.
The initial letter of 'clothes' is 'c'.
'law' after 'c' is 'CLAW'.
(Other definitions for claw that I've seen before include "Hook on the end of toe" , "Rake" , "Hooked nail" , "See 24" , "Crab's pincer" .)