اجتهاد
ijtihād
Scholarly effort to reach a ruling from the sources, when the text does not state it plainly.
What it means
The Prophet said: “When a judge exercises ijtihad and is right he has two rewards, and if he errs he has one” (Sahih al-Bukhari and Sahih Muslim). A scholar qualified in Arabic, the Quran, hadith and the principles of law is called a mujtahid. Ijtihad is how the law meets new cases, from medicine to finance, within the limits of the text and consensus.
What the sources say
The old claim that “the gate of ijtihad was closed” is rejected by many historians, who show that jurists went on giving fresh rulings, and by modern scholars who ask for it to be used more freely.