negligent; careless; slipshod; slovenly; reckless; irresponsible; offhand
彼は投げ遣りに答えた。
He answered carelessly.
彼の投げ遣りな仕事ぶりを上司が咎めた。
His boss reproached him for his sloppy work.
投げ遣りな態度が試験の不合格を招いた。
His negligent attitude led to him failing the exam.