Inexplicable, a.
Etymology: [L. inexplicabilis: cf. F. inexplicable. See In- not, and Explicable.]
Not explicable; not explainable; incapable of being explained, interpreted, or accounted for; as, an inexplicable mystery. "An inexplicable scratching." Cowper. Their reason is disturbed; their views become vast and perplexed, to others inexplicable, to themselves uncertain. Burke.
Shades of meaning
Fernald has no entry of its own for inexplicable; he lists it under mysterious.
He lists it without comment; the entries above explain its neighbors.