Wiktionary
suit up
vb. 1 (context intransitive English) To don a suit, such as a spacesuit or a formal suit. 2 (context transitive English) To clothe, to put clothes on (someone).
Usage examples of "suit up".
O'Neal had accomplished this last feat by the simple expedient of flying his command suit up to the ship and detonating an improvised antimatter limpet mine by hand.
Her enemy never saw it before she had slit his suit up under the right arm.