There's no end to it (8)
I believe the answer is:
eternity
'end to it' is the definition.
The answer and definition can be both states of affairs as well as being singular nouns.
Maybe they are linked in a way I don't understand?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for eternity that I've seen before include "Entirety (anag.)" , "Endless duration" , "Perpetuity" , "Endless period" , "I try teen (anag.)" .)