i-adjective
nonexistent; not there
States that something does not exist or is not present. Often used with が.
There is no parking lot in front of the station.
i-adjective
Used in set phrases like またとない (unparalleled, once-in-a-lifetime) to express that something is rare or exceptional.
See also: またとない
またとない機会を逃した。
I missed a once-in-a-lifetime opportunity.
i-adjective
Used in patterns like ...ことがない to express negation of experience, necessity, or possibility. Often corresponds to 'have never done', 'there is no need to', or 'it cannot happen'.
そんなことはありえない。
That can't happen.
彼に会ったことがない。
I have never met him.
心配することはない。
There's no need to worry.
i-adjective, auxiliary adjective
Auxiliary adjective used after the conjunctive form of an adjective to negate it. Equivalent to 'not' in English.
See also: ない
この部屋は広くない。
This room is not spacious.
今日は寒くない。
It is not cold today.
i-adjective, auxiliary adjective
not (after verb); have not
Auxiliary adjective used after the -te form of a verb to express negation of a state or action. Often translates to 'have not done' or 'is not'.