置 (zhì): To place, to put down, to set aside.
之 (zhī): A classical Chinese grammatical particle that functions here as a pronoun, meaning “it” or “the matter at hand.”
不 (bù): Not, no.
理 (lǐ): To manage, to deal with, to pay attention to, to acknowledge.
The characters combine to form a very literal and vivid picture: “to place it aside and not deal with it.” This structure highlights the two-step process: first the setting aside (置之), and second, the refusal to engage (不理).