One doesn't take meat, say, in delivery vehicle (5)
I believe the answer is:
vegan
'one doesn't take meat' is the definition.
I can't tell whether this definition defines the answer.
'say in delivery vehicle' is the wordplay.
'say' becomes 'eg' (both can mean for example).
'in' is an insertion indicator.
'delivery vehicle' becomes 'van' (I've seen this in another clue).
'eg' placed within 'van' is 'VEGAN'.
Can you help me to learn more?
(Other definitions for vegan that I've seen before include "Person refraining from eating animal products" , "One shunning animal products" , "One not eating animals" , "Strict vegetarian" , "One refusing animal products" .)