IPA: /ʌnˈmjuːzɪkəl/
KK: /ʌnˈmjuzɪkəl/
Not having musical qualities or skills; lacking melody or harmony.
He was considered unmusical because he couldn't carry a tune.
Unmusical → It is formed from "un-" (meaning not) and "musical" (from Latin "musicalis", meaning pertaining to music). The word "unmusical" means not pertaining to music or lacking musical quality.
Think of 'not' ('un-') being added to 'musical', which helps you remember that 'unmusical' describes something that is not musical.