Synset

uninterrupted in time and indefinitely long continuing
<adj.all>   freq. cnt.: 2 freq. cnt.: 2

ceaseless

constant

incessant

never-ending

perpetual

unceasing

unremitting

sample sentences

"the ceaseless thunder of surf"
"in constant pain"
"night and day we live with the incessant noise of the city"
"the never-ending search for happiness"
"the perpetual struggle to maintain standards in a democracy"
"man's unceasing warfare with drought and isolation"
"unremitting demands of hunger"