IPA: //ʌnˈbjuːtəfəli//
KK: /ʌnˈbjuːtəfəli/
In a way that lacks beauty or elegance; in an ugly or unattractive manner.
The painting was unbeautifully done, with harsh colors and awkward shapes.
Unbeautifully → It is formed from "un-" (meaning not) and "beautiful" (from Old French *beauteux*, meaning possessing beauty) and "-ly" (meaning in a manner). The word means in a manner that is not beautiful.
Think of 'not' ('un-') and 'beautiful' — so 'unbeautifully' means in a way that lacks beauty.