May return small vegetables (4)
I believe the answer is:
yams
'vegetables' is the definition.
(yam is a kind of vegetable)
'may return small' is the wordplay.
'return' is a reversal indicator.
'small' becomes 's' (abbreviation - e.g. clothes size).
'may' written backwards gives 'yam'.
'yam'+'s'='YAMS'
(Other definitions for yams that I've seen before include "vegetables" , "Sweet potatoes" , "Edible tubers from the tropics" , "Roots" .)