"character or quality of being sexy," 1922, from sexy + -ness.
Entries linking to sexiness
sexy adj.
1905, "engrossed in sex," from sex (n.) + -y (2). The sense of "sexually attractive" is by 1912. An earlier word in this sense was sexful (1894). Related: Sexier; sexiest.
-ness
word-forming element denoting action, quality, or state, attached to an adjective or past participle to form an abstract noun, from Old English -nes(s), from Proto-Germanic *in-assu- (cognates: Old Saxon -nissi, Middle Dutch -nisse, Dutch -nis, Old High German -nissa, German -nis, Gothic -inassus), from *-in-, originally belonging to the noun stem, + *-assu-, abstract noun suffix, probably from the same root as Latin -tudo (see -tude).