KanjiJLPT N2
Supplement

supplement, supply, make good, offset, compensate, assistant, learner

Mnemonic

At the beginning of a brutal winter, your overcoat is threadbare and full of holes. You must supplement it with thick patches sewn over every gap. By the beginning of spring, the overcoat is more patch than original cloth—but each supplement kept you alive through the cold!
Additional thoughts
Picture yourself desperately sewing patches onto a ragged overcoat at the start of winter. The act of supplementing = filling gaps. Overcoat (衤) + Beginning (甫) = 補.
Quick recall
At the beginning of winter, you supplement your tattered overcoat with patches.

Details

The keyword for 補 is supplement. This kanji conveys the idea of adding something to make up for a deficiency or to fill in what is lacking. It encompasses meanings such as repairing, compensating, reinforcing, or complementing something that is incomplete. The sense is of providing additional support or assistance to restore wholeness or adequacy.
On'yomi
Kun'yomi
おぎな.う