The suffix -less comes from the Old English suffix -leas, from the word leas, meaning “without.” In Old English and Middle English, -less was often used to convey the negative or opposite of words ending in -ful, as in careful/careless and fearful/fearless. But -less was also used to coin words that had no counterpart ending in -ful: headless, loveless, motherless. Although -less normally forms adjectives by attaching to nouns, sometimes it attaches to verbs, as in tireless.
