take up the cudgels for/against someone/something
cudgel
verb[ T ]
uk /ˈkʌdʒ.əl/ us /ˈkʌdʒ.əl/-ll- or US usually-l-
to hit someone with a cudgel棒打，用棍棒打

SMART Vocabulary: related words and phrases

Hitting and beating
at-risk
bang away
bang someone up
basher
bashing
bunch
butt
fetch
gut punch
hammer
head-butt
hell
kick
mess
swing for someone
tan someone's hideidiom
tar
tonk
wallop
whop