What is the meaning of ない?

used to form derivative -i adjectives from other terms: having that quality, having that state; very much that quality or state

nonexistent, not existing, not there, no

not occuring; not being done

not possessed or unavailable for one to use; not having

not reaching a certain quantity, less than

亡い: passed away, dead

unparalleled, unmatched

1. expresses that one hasn't experienced something before

   expresses that one hasn't experienced something before

   expresses that there is no need to do something

   used to negate adjectives and だ (da)

   Used to form the negative of verbs: not, don't

   Source: wiktionary.org