Tool reinvented as a winch (8)
I believe the answer is:
'tool' is the definition.
(I've seen this before)
'reinvented as a winch' is the wordplay.
'reinvented' indicates an anagram.
'asawinch' anagrammed gives 'CHAINSAW'.
(Other definitions for chainsaw that I've seen before include "powered device", "Tree-lopper's tool", "Timber cutter", "Power tool", "Powered cutter".)