所用|しょようshoyou[0]heiban (flat)

1. nounengagement; business; affair
2. no-adjectiveuse; need

• Synonym用件ようけんNeutralThe thing to be done and its content; stresses the specific business at hand. Works in both speech and writing, e.g. 「ご用件」 on the phone. 「所用」 leans written.
• Synonym用事ようじNeutralSomething you have to do; the everyday, most common word. 「所用」 is more written, as in 「所用のため欠席」.
• Synonym用向きようむきNeutralThe purpose of a visit — what someone has come for. Focuses on why the person came rather than the task itself; somewhat old-fashioned.
• Antonym無用むようNeutralUnneeded, useless, or 'not on business' (as on signs barring entry). Antonym of 「所用」, which means having business to attend.

In everyday speech say 「用事」 for something you have to do. In writing, 「所用」 suits 'due to business', as in 「所用で外出」. Use 「用件」 for the content of the matter, 「用向き」 for a visitor's purpose; 「無用」 is the opposite (not needed).

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 用もちいること。用もちいるもの。
2. 用事ようじ。用件ようけん。
3. 必要ひつようなもの。