Non-egg-eater in van, eating mostly egg (5)
I believe the answer is:
vegan
'non-egg-eater' is the definition.
I can't tell whether this defines the answer.
'van eating mostly egg' is the wordplay.
'eating' indicates putting letters inside.
'mostly' means to remove the last letter (most but not all of the word).
'egg' with its last letter taken off is 'eg'.
'van' enclosing 'eg' is 'VEGAN'.
'in' is the link.
Can you help me to learn more?
(Other definitions for vegan that I've seen before include "Strict abstainer from animal products" , "One shunning animal products" , "Person refraining from using animal products in any way" , "One refusing animal products" , "Person neither eating nor using anything animal" .)