Clue: So?a Muslim starts to pray on mat after kneeling (5)
Answer: PAMAK
Explanation: Definition: So?a Muslim
[*starts to*] **P**(ray) **O**(n) **M**(at) **A**(fter) **K**(neeling) 
*Pomaks are Slavic Muslims, so a Muslim from Sofia in Bulgaria may be a Pomak.