Immeasurable, a.
Etymology: [Pref. im- not + measurable: cf. F. measurable. Cf. Immensurable, Unmeasurable.]
Incapble of being measured; indefinitely extensive; illimitable; immensurable; vast. Of depth immeasurable. Milton.
Shades of meaning
Fernald has no entry of its own for immeasurable; he lists it under infinite.
He lists it without comment; the entries above explain its neighbors.