Firm in rush to tan his hide (7)
I believe the answer is:
scourge
'tan his hide' is the definition.
'scourge' can be an answer for 'hide' (thesaurus). I'm unsure of the 'tan his' bit.
'firm in rush' is the wordplay.
'firm' becomes 'co' (a firm is a company).
'in' is an insertion indicator.
'rush' becomes 'surge' (synonyms).
'co' put within 'surge' is 'SCOURGE'.
'to' is the link.
Can you help me to learn more?
(Other definitions for scourge that I've seen before include "administer punishment" , "big nuisance" , "Flog, punish" , "Affliction - whip" , "torment" .)