Ballet dancer's knee bend (4)
I believe the answer is:
plie
'ballet dancer's knee bend' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for plie that I've seen before include "Classic ballet posture" , "Ballet movement bending knees while upright" , "8 [BALLET] term" , "Knees-bend ballet posture" , "Dance move" .)