Unfortunately no elm tree (5)
I believe the answer is:
lemon
'tree' is the definition.
(lemon is a kind of tree)
'unfortunately no elm' is the wordplay.
'unfortunately' indicates anagramming the letters (a bad or unfortunate spelling).
'no'+'elm'='noelm'
'noelm' anagrammed gives 'LEMON'.
(Other definitions for lemon that I've seen before include "Fruit; sort of grass, sole" , "Fruit-tree" , "definitely not a peach" , "Unhelpful answer" , "Fruit high in vitamin C" .)