Clue: Beggar's right to stop one who'll cough up (6)
Answer: PRAYER
Explanation: Definition: Beggar
 R(abbrev. for "right") **contained in**(to stop) PAYER(one who'll cough up/pay the bill).
Defn: One who prays/begs would be a "beg-ger", or ungrammatically, a "beg-gar".
The clue could have done with a homophone indicator.