Gave betel nuts as a food plant (9)
I believe the answer is:
vegetable
'a food plant' is the definition.
(I've seen this before)
'gave betel nuts' is the wordplay.
'nuts' indicates an anagram (nuts can mean crazy).
'gave'+'betel'='gavebetel'
'gavebetel' is an anagram of 'VEGETABLE'.
'as' acts as a link.
(Other definitions for vegetable that I've seen before include "Broccoli eg" , "lady's finger, say" , "Leek?" , "Plant, especially if edible" , "rocket, perhaps" .)