Hotel niff picked up on odd occasions, result of lack of cleaning? (5)
I believe the answer is:
filth
'lack of cleaning?' is the definition.
The answer and definition can be both states of affairs as well as being singular nouns.
Maybe there's an association between them I don't understand?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for filth that I've seen before include "Muck" , "Disgusting dirt or obscenity" , "Carrion" , "Dirt, obscene talk" , "Squalor" .)