Vapers are healthier, pubs half-heartedly admit (8)
I believe the answer is:
inhalers
'vapers' is the definition.
I can't judge whether this defines the answer.
'are healthier pubs half-heartedly admit' is the wordplay.
'are healthier' becomes 'haler' ('hale' can be similar in meaning to 'healthy').
'pubs' becomes 'inns' (an inn is a type of pub).
'half' suggests halving the letters.
'heartedly' becomes 's' (I can't justify this - if you can you should give a lot more credence to this answer).
'admit' indicates putting letters inside.
'inns' cut in half is 'in'.
'in'+'s'='ins'
'haler' put inside 'ins' is 'INHALERS'.
Can you help me to learn more?
(Other definitions for inhalers that I've seen before include "Magnate" , "Gas masks" .)