expression, i-adjective
very rare; very unlikely; almost never
Expresses that something is extremely improbable or almost never happens. Often used in negative contexts or with a negative verb form.
彼が遅刻するのはまず無い。
It's very rare for him to be late.
こんなチャンスはまずない。
An opportunity like this is very unlikely.
Similar meaning, but 滅多にない is more common in spoken Japanese and often used with a negative verb, while まず無い is slightly more emphatic and can stand alone as an adjective.
Compound of the adverb まず (mostly, almost) and the negative form of ある (to exist), literally 'almost not exist'. The exact historical derivation is straightforward.