IPA: /nɒnɪɡˈzɛstənʃəl/
KK: /nɑnɪɡzɛstəntʃəl/
Not related to existence or being.
The concept of nonexistential threats is often discussed in philosophy.
Nonexistential → It is formed from "non-" (meaning not) and "existential" (from Latin "existere", meaning to stand out or to exist). The word "nonexistential" refers to something that does not exist or is not related to existence.
Think of 'non-' meaning 'not' and 'existential' relating to 'existence' — so nonexistential means something that does not relate to existence.