The Collaborative International Dictionary of English v.0.48:
Outmost \Out"most`\, a. [OE. outemest, utmest, AS. [=u]temest, a superl. fr. [=u]te out. See Out, Utmost, and cf. Outermost.] Farthest from the middle or interior; farthest outward; outermost. [1913 Webster]WordNet (r) 3.0 (2006):
outmost adj 1: situated at the farthest possible point from a center [syn: outermost, outmost]