UNMUSICAL
unmelodious, unmelodic, unmusical
(adjective) lacking melody
unmusical, nonmusical
(adjective) not musical in nature; “the unmusical cry of the bluejay”
unmusical, nonmusical
(adjective) lacking interest in or talent for music; “too unmusical to care for concerts”; “it is unfortunate that her children were all nonmusical”
Source: WordNet® 3.1
Etymology
Adjective
unmusical (comparative more unmusical, superlative most unmusical)
Not musical: lacking in musical ability.
Not musical: unmelodic.
Source: Wiktionary