na-adjective, noun which may take the genitive case particle 'no', noun
disused; unused; out of use
Describes something that is no longer used or has fallen out of use. Often used for objects, facilities, or systems that are not currently in service.
See also: 不要
na-adjective, noun, noun which may take the genitive case particle 'no'
Indicates that something serves no purpose or is a waste. Often used in phrases like 不用なもの (useless things) or 不用な出費 (wasteful spending).
This room has been unused for a long time.
I dispose of furniture that is no longer used.
I try not to buy useless things.
The plan led to wasteful spending.
不用 (same reading as 不要) describes something no longer used or discarded, while 無用 more broadly covers uselessness, needlessness, and fixed prohibitive expressions.
不用 means unnecessary or useless, while 不用意 means careless or unprepared; the similar spelling often causes learners to mix them up.
Compound of 不 (not) and 用 (use). The spelling is straightforward, but note the homophone 不要 (not necessary), which is more frequent.