Trendy joint (3)
I believe the answer is:
hip
I believe this clue is a double definition.
'trendy' is the first definition.
(I've seen this before)
'joint' is the second definition.
(part of body)
(Other definitions for hip that I've seen before include "it can nowadays be replaced" , "Following trends" , "Slangily stylish like rose fruit" , "Fruit of the wild rose (3)" , "Leg joint" .)