Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.

WORD ORIGIN

early 15c., "displeasing to the eye," from un- (1) "not" + sight + -ly (1). Cf. Middle Dutch onsichtlijc "invisible; ugly," Middle High German unsihtlih "invisible." Related: Unsightliness. Middle English sightlie is attested from mid-15c. but only in the sense "visible;" sightly as "pleasing to the eye" is from 1560s.

Roget's 21st Century Thesaurus, Third Edition Copyright © 2013 by the Philip Lief Group.