Supplication from one who coughs up is about right (6)
I believe the answer is:
prayer
'supplication' is the definition.
(synonyms)
'one who coughs up is about right' is the wordplay.
I cannot really understand how this works, but
'one' could be 'er' (I've seen this in other clues) and 'er' is located in the answer.
'about' could be 'a' (abbreviation in Chambers) and 'a' is present in the answer.
'right' could be 'r' (common abbreviation) and 'r' is present in the answer.
This may be the basis of clue (or it may be nonsense).
'from' acts as a link.
Can you help me to learn more?
(Other definitions for prayer that I've seen before include "Addressed God" , "Collect - petition" , "Paternoster, for example" , "Invocation, entreaty" , "request for help?" .)