Fruit brown, green is unlikely (10)
I believe the answer is:
tangerines
'fruit' is the definition.
(I've seen this before)
'brown green is unlikely' is the wordplay.
'brown' becomes 'tan' (tan is a kind of brown).
'unlikely' indicates anagramming the letters.
'green'+'is'='greenis'
'greenis' anagrammed gives 'gerines'.
'tan'+'gerines'='TANGERINES'
(Other definitions for tangerines that I've seen before include "fruit" , "Citrus fruits" , "Natives of Tangiers" .)