Bizarrely, lets us fight (6)
I believe the answer is:
tussle
'fight' is the definition.
(I know that tussle is a type of fight)
'bizarrely lets us' is the wordplay.
'bizarrely' indicates anagramming the letters.
'lets'+'us'='letsus'
'letsus' with letters rearranged gives 'TUSSLE'.
(Other definitions for tussle that I've seen before include "Go at it" , "A struggle or conflict" , "'Scuffle, rough-and-tumble (6)'" , "'Physical fight, struggle (6)'" , "Skirmish" .)