"tendency toward self-assertion," 1867, short for self-assertiveness (1855); see assertive + -ness.
Entries linking to assertiveness
assertive adj.
1560s, "declaratory, positive, full of assertion," from assert (v.) + -ive. The meaning "insisting on one's rights or authority" is short for self-assertive.
-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).