Carelessly sat in green fruit (10)
I believe the answer is:
tangerines
'fruit' is the definition.
(I've seen this before)
'carelessly sat in green' is the wordplay.
'carelessly' indicates an anagram.
'sat'+'in'+'green'='satingreen'
'satingreen' is an anagram of 'TANGERINES'.
(Other definitions for tangerines that I've seen before include "fruit" , "Natives of Tangiers" , "Citrus fruits" .)