補

補

"補" means "to supplement" or "to compensate."

The kanji '補' here is part of '補欠', meaning 'substitute' or 'replacement'.

彼は選挙で補欠に選ばれた。

He was selected as a substitute in the election.

The kanji '補' in '補足' means 'to supplement' or 'to add.'

この資料を使って授業内容を補足します。

I will supplement the class content using this material.

The kanji '補' in '補給' means 'to replenish' or 'to supply.'

痛みを抑えるためにビタミンを補給します。

I replenish vitamins to mitigate the pain.