IPA: /ˌɪnəˈθɛntɪsɪti/
KK: /ɪnɔˈθɛntɪsɪti/
The condition of not being genuine or real; a lack of authenticity.
The inauthenticity of the product was evident to the customers.
Inauthenticity → It is formed from "in-" (meaning not) and "authenticus" (from Greek "authentikos", meaning genuine or real) and "-ity" (meaning the state or quality of). The word refers to the state of being not genuine or not real.
Think of 'not' ('in-') and 'genuine' ('authenticus') to remember that 'inauthenticity' means the quality of being not genuine.