後任は英語で
successor

英語の定義

後任
1. n. successor
彼は後任として足立さんを指名した。 - He appointed Ms. Adachi as his successor.

successor
1. 名詞. 後任。後継。継承。
George W. Bush was successor to Bill Clinton as President of the US.
米国大統領で、ビル・クリントンの次は、ジョージ・W・ブッシュである。
2. 名詞. 相続人。
3. 名詞. 後継者。継承者。
4. 名詞. (mathematics) 後者。

successor
1. n. A person or thing that immediately follows another in holding an office or title.
George W. Bush was successor to Bill Clinton as President of the US.
2. n. The next heir in order or succession.
3. n. A person who inherits a title or office.
4. n. (arithmetic, set theory) The integer, ordinal number or cardinal number immediately following another.
A limit ordinal is not the successor of any ordinal.