Fellow left tree in blaze (5)
I believe the answer is:
flash
'blaze' is the definition.
(thesaurus)
'fellow left tree' is the wordplay.
'fellow' becomes 'f' (abbreviation - of a society etc.).
'left' becomes 'l' (common abbreviation).
'tree' becomes 'ash' (ash is a kind of tree).
'f'+'l'+'ash'='FLASH'
'in' acts as a link.
(Other definitions for flash that I've seen before include "Brandish" , "type of photography" , "Quick burst of light" , "Tasteless" , "sort of flooding" .)