Girl has trendy fruit (7)
I believe the answer is:
rosehip
'fruit' is the definition.
(fruit of a rose plant)
'girl has trendy' is the wordplay.
'girl' becomes 'rose' ().
'has' says to put letters next to each other.
'trendy' becomes 'hip' (both can mean fashionable).
'rose'+'hip'='ROSEHIP'
(Other definitions for rosehip that I've seen before include "Hedgerow or garden fruit" , "Red fruit" , "Fruit on wild plant" , "Part of plant" , "Wild fruit for syrup" .)