KanjiJLPT N1
Expel

repudiate, exclude, expel, reject, line up, arrange

Mnemonic

Your hand reaches into the prison and yanks out an inmate the other prisoners despise. You expel him completely—shoved through the gates by hand, rejected even by criminals. Nobody wants this guy around, so he's cast out into the wilderness alone.
Additional thoughts
Picture a giant hand bursting through prison bars, grabbing someone, and hurling them out. Even convicts have standards—this person is so awful the prison itself rejects them.
Quick recall
A hand drags someone out of prison to expel them—even criminals don't want him.

Details

The keyword for 排 is expel. This kanji conveys the meaning of pushing away, driving out, or rejecting something. It implies a forceful act of removal or exclusion, whether physically pushing things aside or figuratively opposing and eliminating unwanted elements. The character also extends to the idea of arranging or lining things up in order, as if pushing items into their proper positions.
On'yomi
はい