Don't criticise article by expressing hesitation - it will put one to sleep (8)
I believe the answer is:
laudanum
'sleep' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'don't criticise article by expressing hesitation it will put one' is the wordplay.
I cannot quite see how this works, but
'article' could be 'an' (indefinite article) and 'an' is present in the answer.
'hesitation' could be 'um' and 'um' is found within the answer.
'one' could be 'a' and 'a' is found in the answer.
The remaining letters 'lud' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
'to' acts as a link.
Can you help me to learn more?
(Other definitions for laudanum that I've seen before include "Formerly respectable drug" , "Former painkiller" , "Narcotic of choice in old novels" , "Coleridge took this" , "Tincture of opium" .)