IPA: /ˌɪnɪˈmɪtəblnəs/
KK: /ɪˌnɪmɪˈtæblnəs/
The quality of being impossible to imitate or copy; uniqueness.
The artist's inimitableness made her work stand out in the crowded gallery.
Inimitableness → It is formed from "in-" (meaning not), "imitari" (meaning to imitate), and "-ness" (meaning the state of being). The word describes the state of being not able to be imitated, highlighting uniqueness or singularity.
Think of 'not' ('in-') being able to 'imitate' ('imitari') something — that's why inimitableness means the quality of being unique or unmatched.