"state or quality of being prompt," 1520s, from prompt (adj.) + -ness.
Entries linking to promptness
prompt adj.
early 15c., "ready, prepared (to do something), quick to act as occasion demands," from Old French prompt (13c.) and directly from Latin promptus "brought forth," hence "visible, apparent, evident, at hand," past-participle adjective from promere "to take or bring out or forth" (see prompt (v.)). Meaning "given or performed without delay" is from 1520s. Related: Promptly.
-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).