Stuff finished before tea-break (7)
I believe the answer is:
overeat
'stuff' is the definition.
('overeat' can be a synonym of 'stuff')
'finished before tea-break' is the wordplay.
'finished' becomes 'over' ('over' can be similar in meaning to 'finished'**).
'before' says to put letters next to each other.
'break' is an anagram indicator.
'tea' is an anagram of 'eat'.
'over'+'eat'='OVEREAT'
(Other definitions for overeat that I've seen before include "Take too much food" , "Consume too much food, stuff your stomach" , "Be gluttonous" , "pig out?" , "Take in excess" .)