fitful

The word "fitful" is a relatively modern English formation, first appearing in the early 17th century. It is built upon the older noun "fit," which in Middle English (from Old English fitt) originally denoted a struggle or conflict, later developing the sense of a sudden, temporary attack or paroxysm of activity, emotion, or illness. By adding the adjectival suffix "-ful," meaning "full of" or "characterized by," the word literally means "full of fits." This construction directly conveys the modern meaning: characterized by intermittent bursts of activity followed by pauses, resulting in an irregular and restless pattern.

Structure: fit (act, spell) + ful (full of) - fit (Middle English, from Old English fitt): A noun meaning a struggle, a conflict, or a paroxysm. In this context, it evolved to mean a sudden, short period of activity or feeling. - ful (Old English -ful): An adjective-forming suffix meaning "full of" or "characterized by."