Wiktionary
unmusically
adv. In an unmusical way.
WordNet
unmusically
adv. in an unmusical manner; "She sings rather unmusically" [ant: musically]
Usage examples of "unmusically".
It moved me to tears, but unmusically, I'm afraid, because it made me think of Dear One (who isn't in the least ready for Death) and her struggle in this ghastly place where they haven't the least idea of her quality.