a reply; an answer or response to a question or remark, usable in both spoken and written contexts (sometimes a bit formal).
彼の提案に対して明確な返答を求めた。
I asked for a clear response to his proposal.
上司からの質問にすぐに返答できなかった。
I couldn't answer my boss's question immediately.
まだ返答が来ていないので確認します。
I will check because I haven't received a reply yet.