Some call it Isis. Others say it's Isil. The group itself prefers Islamic State, or IS. And in the Middle East, its critics call it Da'ash.

Now Islamic State in Iraq and Syria has been given a fifth name, and perhaps its oddest: QSIS. Standing for al-Qaida Separatists in Iraq and Syria. The rebrand is an influential Islamic institution's attempt to stop the militant group smearing the reputation of Islam.

"What the western world calls the 'Islamic State' is in no way related to Islam," said Egypt's Dar al-Ifta, a wing of the Egyptian justice ministry that plays a small role in both Egypt's judicial system and in global Islamic discourse. Considered a source of religious authority both inside and outside Egypt, Dar al-Ifta issues religious guidance (or fatwas) to Sunni Muslims across the world who request advice on religious ambiguities.

Its latest intervention concerns the naming of Isis: Dar al-Ifta wants western journalists to refer to the group as QSIS in order to emphasise to non-Muslims that the group's extremist ideology and depravity does not represent Islam's vast majority. Despite their name, Isis (or QSIS, to use the new coinage) militants are "far from the correct understanding of Islam", said Dar al-Ifta's head, Grand Mufti Shawki Allam.

To ram home its point, Dar al-Ifta has asked social media users to join a new Facebook group, "Call it QS not IS".

But it remains to be seen whether Dar al-Ifta can persuade a global body politic already bitterly divided on what to call the group. Before commuting its Arabic name to the simpler al-Dawla al-Islamiya (or "Islamic State"), Isis called itself al-Dawla al-Islamiya fi Iraq wa al-Sham. Everyone agreed on how to translate the first five words of the moniker, but the sixth – al-Sham – has triggered endless linguistic battles. Some feel Sham can be translated as Syria. Others say Greater Syria. Still more argue for the Levant, and a few think it should be left as it is.

For some, QSIS might be a good compromise. But then, others may prefer QSIL.