Mujtahid
From WikiIslam
A mujtahid is a Muslim jurist who is qualified to interpret the law and thus to generate Ijtihad.
The qualifications for a mujtahid were set out in the 11th century by Abul Husayn al-Basri in "al Mu’tamad fi Usul al-Fiqh". These were and accepted by later Sunni scholars, including al-Ghazali, although al-Ghazali believed that innovation had ended, as there was nobody qualified to be a Mujtahid. Such qualifications require proficiency in Sha'aria and its interpretation.