What's the difference between unmusical and unmusically?

Unmusical

Definition:

Example Sentences:

(1) Indeed, can we not say of Kafka, that far from being unmusical, he was far too musical for the conventional music to which he was at first subjected?
(2) Brod, always at pains to airbrush Kafka's image into hazy iconography – and possessing that sense of his own cultured condition beloved of the second-rate artist – won't allow that Kafka was unmusical: "he possessed a natural feeling for rhythm and tune," and he recounts that he used to "drag him along to concerts until I gave it up, when I found his reactions to them were of a purely visual character".
(3) Each pattern was strongest in experienced pianists' performances and decreased when pianists attempted to play unmusically.
(4) After all, what could be a more tactful reaction to a friend's bad piano setting of your poetry than to evade direct comment by claiming to be unmusical?

Definition:

Example Sentences:

(1) Indeed, can we not say of Kafka, that far from being unmusical, he was far too musical for the conventional music to which he was at first subjected?
(2) Brod, always at pains to airbrush Kafka's image into hazy iconography – and possessing that sense of his own cultured condition beloved of the second-rate artist – won't allow that Kafka was unmusical: "he possessed a natural feeling for rhythm and tune," and he recounts that he used to "drag him along to concerts until I gave it up, when I found his reactions to them were of a purely visual character".
(3) Each pattern was strongest in experienced pianists' performances and decreased when pianists attempted to play unmusically.
(4) After all, what could be a more tactful reaction to a friend's bad piano setting of your poetry than to evade direct comment by claiming to be unmusical?