Leave just a wisp (6)
I believe the answer is:
strand
This clue is a double definition.
'leave' is the first definition.
'just a wisp' is the second definition.
(Other definitions for strand that I've seen before include "Ply" , "Leave helpless - length of fibre" , "that may be found by the sea" , "Yarn - thread" , "Single piece of hair, rope etc" .)