unending
The officer said the prisoner talked unendingly about his desire to move to a different part of the Camp.
They believed that after God's judgment we shall be unendingly happy or unendingly miserable.
He found the sport of cricket unendingly fascinating.
It's one of the most tragic, unendingly upsetting, disturbing books I've ever read.

SMART Vocabulary: related words and phrases

Continuous & permanent
abiding
abidingly
ad infinitum
around-the-clock
be
here to stayidiom
immanence
immanent
immanently
imperishable
on the bounceidiom
on the spinidiom
on the trotidiom
perennial
permanence
unrelentingly
unrelieved
unrelievedly
unremitting
unremittingly

You can also find related words, phrases, and synonyms in the topics:

Continually & repeatedly
Linguistics: very & extreme