Cut-price vegetarian food (3)
I believe the answer is:
cos
'vegetarian food' is the definition.
'cos' can be an answer for 'food' (I have seen 'healthy food' mean 'cos' so perhaps 'food' could also mean 'cos'). I am unsure of the 'vegetarian' bit.
'cut-price' is the wordplay.
'cut' means to remove the last letter.
'price' becomes 'cost' (synonyms).
'cost' with its last letter removed is 'COS'.
Can you help me to learn more?
(Other definitions for cos that I've seen before include "Salad plant" , "Mozart fidelity-test opera" , "Kind of lettuce in microcosm" , "in the Dodecanese?" , "Senior officers" .)