Little monkey’s limb held by medic to repair break (8)
I believe the answer is:
marmoset
'little monkey's' is the definition.
(I've seen this before)
'limb held by medic to repair break' is the wordplay.
'limb' becomes 'arm' (arm is a kind of limb).
'held by' is an insertion indicator.
'medic' becomes 'mo' (medical officer).
'to repair break' becomes 'set' (I can't explain this - if you can you should believe this answer much more).
'arm' inserted inside 'mo' is 'marmo'.
'marmo'+'set'='MARMOSET'
Can you help me to learn more?
(Other definitions for marmoset that I've seen before include "Small New World monkey" , "Primate" , "Small tropical American monkey" , "Small monkey - Rome's mat (anag)" , "Small bushy-tailed monkey" .)