Corkscrew shape (6)
I believe the answer is:
spiral
'corkscrew shape' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for spiral that I've seen before include "Whorl" , "Corkscrew shape (6)." , "In flight manoeuvre" , "Helical shape" , "Corkscrew curve" .)