The Collaborative International Dictionary of English v.0.48:
Unmeasurable \Un*meas"ur*a*ble\, a. Immeasurable. --Swift. -- Un*meas"ur*a*ble*ness, n. -- Un*meas"ur*a*bly, adv. [1913 Webster]WordNet (r) 3.0 (2006):
unmeasurable adj 1: impossible to measure; "unmeasurable reaches of outer space" [syn: immeasurable, unmeasurable, immensurable, unmeasured] [ant: measurable, mensurable]