IPA: //ʌnˈstaɪlɪʃ//
KK: /ʌnˈstaɪlɪʃ/
Not fashionable or attractive in style.
She wore an unstylish outfit that didn't match the latest trends.
Unstylish → It is formed from "un-" (meaning not) and "stylish" (from the root "style" which comes from Old French *estile*, meaning a manner of doing something). The word "unstylish" means not having style or lacking in fashionable appearance.
Think of 'not' ('un-') having a 'manner' or 'style' — that's why 'unstylish' means lacking style.