Disuse (; see Dis-), v. t. [imp. & p. p. Disused; p. pr. & vb. n. Disusing.] — Webster enters it under “disuse”
1. To cease to use; to discontinue the practice of.
2. To disaccustom; -- with to or from; as, disused to toil. "Disuse me from . . . pain." Donne.
1 other Webster entry under this spelling
Disuse, n.
Cessation of use, practice, or exercise; inusitation; desuetude; as, the limbs lose their strength by disuse. The disuse of the tongue in the only . . . remedy. Addison. Church discipline then fell into disuse. Southey.
Shades of meaning
Fernald has no entry of its own for disused; he lists it under obsolete.
He lists it without comment; the entries above explain its neighbors.