KanjiJLPT N1
Repel

instead, on the contrary, rather, step back, withdraw, retreat

Mnemonic

To repel an unwelcome guest, stamp your feet furiously at the doorway until he's gone! Each thunderous stamp shakes the whole floor, and the intruder scrambles backward, gone before you even break a sweat.
Additional thoughts
Picture the physical act: stamping drives someone away (repels them) until they're gone. The force of the stamp is what causes the repelling, and the result is them being gone.
Quick recall
Stamp your feet until the intruder is gone—that's how you repel.

Details

The keyword for 却 is repel. This kanji conveys the idea of driving back, rejecting, or pushing something away. It carries the sense of declining or refusing something that has been offered or presented, effectively sending it back from where it came. By extension, it can also suggest the notion of stepping back or retreating from a position, reinforcing the core meaning of turning something away or dismissing it.
On'yomi
きゃく
Kun'yomi
かえ.って、しりぞ.く、しりぞ.ける

Used in kanji