Swear, dear? I will have show of hesitation: it pollutes the air (9)
I believe the answer is:
effluvium
'air' is the definition.
The answer and definition can be both substances as well as being singular nouns.
Maybe there's an association between them I don't understand?
'swear dear? i will have show of hesitation it pollutes' is the wordplay.
I cannot really understand how this works, but
'i' is found in the answer.
'have' could be 'eff' (synonyms) and 'eff' is found within the answer.
'hesitation' could be 'um' (sound made when hesitating) and 'um' is present in the answer.
The remaining letters 'luv' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'the' is the link.
Can you help me to learn more?
(Other definitions for effluvium that I've seen before include "Smell of decaying matter" , "Unpleasant smell" .)