There is a bit of creed in the name ‘Muslim’, since it communicates that the true believer is one who does not challenge God and his will, and who tries to live his/her life according to the rules without questioning them.
The word ‘Muslim’ uses the same root as ‘Islam’: s-l-m.
According to many Muslim thinkers and theologians, the word Muslim is considered a quality that not all inhabitants in the Muslim world can claim. A majority of the people are considered as believers (mu’min), which is less than being a Muslim. A Muslim is a person who is intentional in trying to lead his/her life according to God’s will, while the mu’min (believer) is one who chooses the easier path, and lets his/her needs dictate the action.
Most Muslims use the term ‘true Muslim’ for the really devout, which means that all people belonging to Islam are considered Muslim, even if they are not practicing Muslims. Research (Tore Kjeilen) in Tunisia in 1994 showed that about 40% of the population are practicing Muslims, while 50% participate only in major holidays. Slightly less than 10% are not active at all.
Atheists exist in all Muslim countries, yet because they seldom exceed 1-3% of the population, they often designate themselves as Muslim, since they identify with Muslim culture and world view.
The word may also be used to distinguish between ideas and customs that are clearly in correspondence with the original Islam, and those that must from a neutral point of view be considered deviations or ideas and customs that certain Muslim groups disagree over. Original ideas and customs are then labeled “Islamic”, those not are labelled “Muslim”.