kənˈtinyəwəl, -yəl adjective
Etymology: Middle English, from Middle French continuel, from Latin continuus continuous + Middle French -el -al — more at continuous
1. : continuing in time : proceeding without stopping, interruption, or intermission : going on indefinitely — now used only of things
the continual dread of falling into poverty which haunts us all at present — G.B.Shaw
2. : recurring in steady and rapid succession : repeated at intervals with brief perhaps regular intermissions in time
continual storm … with frequent showers of snow — William Wordsworth
3. obsolete
a. : continuously acting or engaged : constant
b. of disease : chronic
c. : forming a continuous series or whole : unbroken
Synonyms:
continuous , constant , incessant , unremitting , perpetual , perennial : continual and continuous indicate lasting occurrence or presence over long periods
we live in a country where his Majesty's Cabinet governs subject to the continual superintendence, correction, and authority of Parliament — Sir Winston Churchill
the new struggle was continuous, the old had been sporadic — Lewis Mumford
continual is somewhat more common than continuous in describing intermittent action, but both words are well-established and satisfactory in this sense
the century and a half that followed the gathering of the estates at Westminster was a time of almost continual war — J.R.Green
continual and regular impulses of pleasurable surprise from the metrical arrangement — William Wordsworth
continuous landslides raised the cost of maintenance so high that a loss was sustained each year — American Guide Series: Connecticut
Unlike continual in this respect, continuous may apply to space as well as time
the continuous plains of the Great Lowland overlap from the Continental and Arctic drainage of the Heartland into the east of the European peninsula — H.J.Mackinder
constant strongly implies lasting steadiness, lack of change, or uniformity
unfortunately, perhaps, experience does not grow at a constant, but at an accelerated, rate — J.W.Krutch
personal goodness … of a very fitful cast — an occasional almost oppressive generosity rather than a mild and constant kindness — Thomas Hardy
incessant suggests virtually ceaseless uninterrupted activity
his incessant talking and shouting and bellowing of orders had been too much — Jack London
over that which we call the meaning of the words a poet uses, there goes on an incessant play of suggestion, caught from each user's own adventures among words — J.L.Lowes
unremitting indicates unceasing activity without slackening or halting
sporadic outbursts are converted by the rationalization into purposive and unremitting activity — Aldous Huxley
the men fifteen or twenty paces apart, all in concealment and under injunction of strict silence and unremitting vigilance — Ambrose Bierce
perpetual indicates lasting duration or unfailing repetition
sins unatoned for and uncondoned bring purgatorial or perpetual torment after death, even as holiness brings eternal bliss — H.O.Taylor
their heroic defense will be recorded for all time. It will be perpetual proof that democracy … can show the stuff of which it was made — F.D.Roosevelt
weary … of perpetual state business and perpetual honors; he wanted a rest — Robert Graves
perennial connotes either existence over a long period or certain recurrence
those who have lived before such terms as “highbrow fiction”, “thrillers”, and “detective fiction” were invented realize that melodrama is perennial — T.S.Eliot
to all who profess faith in the democratic ideal Jefferson is a perennial inspiration — V.L.Parrington