Found groom his stable (9)
I believe the answer is:
establish
'found' is the definition.
(found can mean to set up or establish)
'groom his stable' is the wordplay.
'groom' indicates an anagram.
'his'+'stable'='hisstable'
'hisstable' anagrammed gives 'ESTABLISH'.
(Other definitions for establish that I've seen before include "Set up or found" , "Set up or bring into existence" , "Verify" , "Found - his stable (anag)" , "Set up a business or prove to be true" .)