Twig it's not your own hair (6)
I believe the answer is:
switch
'twig' is the definition.
(thesaurus)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for switch that I've seen before include "Get change" , "Light whip - light control" , "Device for completing or breaking an electrical circuit" , "Swap" , "Cane to control the light" .)