noun which may take the genitive case particle 'no', noun
unnecessary; useless; unwanted
Describes something or someone that is not needed or has no purpose. Often used in the phrase 用無しになる (become useless/unnecessary).
この書類はもう用無しだ。
These documents are no longer needed.
彼は会社で用無しになった。
He became useless at the company.
noun which may take the genitive case particle 'no'
having nothing to do; idle; unoccupied
Refers to a state of having no tasks or being free. Often used with で to describe a person's situation.
今日は用無しで、一日中家にいた。
I had nothing to do today, so I stayed home all day.
不要 is more formal and objective, meaning 'unnecessary' or 'not required', while 用無し is more colloquial and can imply being useless or having no role.
暇 means 'free time' or 'leisure', whereas 用無し emphasizes the lack of tasks or purpose, often with a negative nuance.
Compound of 用 (you, 'business' or 'task') and 無し (nashi, 'without'). The spelling 用無し uses the kanji 無 for 'nothing'.