Underused vs. Misused

Underusedadjective

Used less than normal or desirable.

Misusedadjective

Used in an incorrect or inappropriate manner.

‘The oft misused word didn't mean what he thought it meant, but everyone else misunderstood it too.’;

Underusedverb

simple past tense and past participle of underuse

Misusedverb

simple past tense and past participle of misuse

Misusedadjective

used incorrectly or carelessly or for an improper purpose;

‘misused words are often laughable but one weeps for misused talents’;