The name on the collar says "Scamp" (7)
I believe the answer is:
ruffian
'says scamp' is the definition.
'ruffian' can be an answer for 'scamp' (thesaurus). I am unsure of the 'says' bit.
'the name on the collar' is the wordplay.
'the name' becomes 'ian' ().
'on' means one lot of letters go next to another.
'the collar' becomes 'ruff' (ruff is a kind of collar).
'ian' put after 'ruff' is 'RUFFIAN'.
Can you help me to learn more?
(Other definitions for ruffian that I've seen before include "Yobbo" , "Hoodlum" , "Roughneck" , "Bully" , "Lout" .)