Goes off lettuce (6)
I believe the answer is:
leaves
'goes off' is the definition.
(I've seen this in another clue)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for leaves that I've seen before include "Departs with what fall in the Fall" , "Organs of photosynthesis" , "Steps out of" , "Departs with tree growths" , "Rocket, for example" .)