Tough left restaurant, having consumed hot starter (8)
I believe the answer is:
leathery
'tough' is the definition.
('leathery' can be a synonym of 'tough')
'left restaurant having consumed hot starter' is the wordplay.
'left' becomes 'l' (common abbreviation).
'restaurant' becomes 'eatery' (I've seen this before).
'having consumed' indicates putting letters inside.
'hot starter' becomes 'h' (I can't explain this - if you can you should believe this answer much more).
'eatery' placed around 'h' is 'eathery'.
'l'+'eathery'='LEATHERY'
(Other definitions for leathery that I've seen before include "Tough (meat, hide)" , "like old boots?" , "Tough, wrinkled (skin)" , "Like a football" , "Like tough skin" .)