Fitful means stopping and starting, and never steady. Fitful sleep, fitful progress, a fitful breeze.
Fitful sleep is the commonest use, and it names broken sleep rather than short sleep — waking repeatedly costs more than going to bed late. The fit in it is the old sense of a bout or attack rather than the modern one.
1adjectivefitfulStopping and starting, and never steady.
“The wind came in fitful gusts, rattling the windows and then dying away again.”
fitful is a quality of irregularity.
Fit plus -ful, from fit in the old sense of a sudden bout or attack rather than the sense of suitable.
From fit + ful.
Etymology from Wiktionary, CC BY-SA