IPA: //ʌnˈæp.ɪ.taɪ.zɪŋ//
KK: /ʌnˈæpɪˌtaɪzɪŋ/
Not appealing or inviting to eat, often because it looks or smells bad.
The food looked unappetizing and I didn't want to try it.
Unappetizing → It is formed from "un-" (meaning not) and "appetizing" (from Latin "appetitus", meaning desire or craving, combined with the suffix "-ing" which indicates the action or process). The word "unappetizing" means not appealing or lacking in desire to eat.
Think of 'not' ('un-') making something 'desirable to eat' ('appetizing') — that's why unappetizing means it doesn't make you want to eat.