Shy away on the subject of company I left (6)
I believe the answer is:
recoil
'shy away' is the definition.
(thesaurus)
'the subject of company i left' is the wordplay.
'the subject of' becomes 're' (I've seen this in other clues).
'company' becomes 'co' (abbreviation).
'left' becomes 'l' (common abbreviation).
're'+'co'+'i'+'l'='RECOIL'
'on' acts as a link.
(Other definitions for recoil that I've seen before include "Flinch, shrink back in fear" , "withdraw" , "Flinch, starts back" , "Cringe" , "Kick of gun" .)