Put-up-one-s-dukes Definition

verb

(idiomatic) To raise one's clenched fists in front of one's body and stand in a threatening or defiant manner, in preparation for a fistfight.

Wiktionary

(idiomatic, by extension) To take firm action or to show oneself to be committed to such action, as when competing in a sporting event or other contest.

Wiktionary

Origin of Put-up-one-s-dukes

Possibly by analogy to a king or other ruler summoning his dukes, and by extension the duke's knights or other soldiers, to battle an enemy. Or possibly Cockney rhyming slang (see duke).

From Wiktionary