Burn tea (4)
I believe the answer is:
char
I believe this clue is a double definition.
'burn' is the first definition.
(charring is a kind of burning)
'tea' is the second definition.
(I've seen this before)
(Other definitions for char that I've seen before include "Tea (sl.)" , "House cleaner" , "Partly burn - cleaning woman" , "Clean < fish" , "Become black by burning" .)