Speaking without thinking; saying something offhand or without basis (often improvised or careless remark).
彼女は責任を取ると言ったが、それはただの出任せだった。
She said she would take responsibility, but that was just an offhand remark.
面接で出任せに答えると信頼を失うことがあるから注意しなさい。
Be careful not to answer offhand in an interview; you can lose trust that way.
その数字は出任せで言ったものじゃなく、ちゃんと調べた結果です。
Those figures weren't spoken offhand; they are the result of proper research.