Thor loses nothing with wood hammer (6)
I believe the answer is:
thrash
'hammer' is the definition.
(thesaurus)
'thor loses nothing with wood' is the wordplay.
'loses' suggests deleting specific letters.
'nothing' becomes 'o' (looks like zero - 0).
'with' says to put letters next to each other.
'wood' becomes 'ash' (I've seen this before).
'thor' with 'o' taken away is 'thr'.
'thr'+'ash'='THRASH'
(Other definitions for thrash that I've seen before include "Beat; party (colloq.)" , "Noisy, lavish party" , "Beat hard" , "Beat up, batter" , "stuff" .)