Sayyed Mohammad Al-Musawi, Sayyed Mohammad al-Musawi is originally from Iraq and heads up the World Ahlul Bayt Islamic League in London. Other than being involved in various humanitarian projects, he frequently responds to... Answered 2 years ago

The linguistic meaning of it is (Peace be upon him) which is in fact used for every Muslim when you say to him : Salamun Alaykum.(Peace be upon you).

But as a term and common understanding , we have to be careful in using it to avoid mixing between the Infallible and others.