Islam vs. Muslim
Many people found it difficult to differentiate between the Islam and Muslim as both these terms are interrelated or in other words, we can say that one Muslim is the subset of the Islam. To understand both these terms, we need to get the broader concept of what the religion is. Here it should be kept noted that the religion is the fundamental set of beliefs agreed and practiced by the individuals or group; this set of beliefs mainly comprises of the issues mentioned below. The purpose of the universe, especially when considered as the creation of a superhuman agency or agencies, usually involving devotional and ritual observances, and often containing a moral code governing the conduct of human affairs; these all are the important point of the religion. Currently, there are over 4200 religions in the world, out of which Islam is the second most popular religion after falling second to the Christianity. And the one who follows or practices Islam is called the Muslim.

Key Differences
Shahadah, Salat (prayers), Zakat (charity), Fasting and visit to Holy Kabaah are the five pillars of Islam.
Islam is the second largest religion as it has over 1.6 billion followers (Muslims).
Islam is the religion which obliges it followers to follow the teachings of Quran, the oneness of ALLAH, and Muhammad PBUH as the last prophet, whereas the one accepts and practices this religion is called Muslim.
Islam is only one, although Muslims get divided further by sects and beliefs.
Comparison Chart
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Islam is the religion which obliges it followers to follow the teachings of Quran, the oneness of ALLAH, and Muhammad PBUH as the last prophet.
The one accepts and practices this religion is called Muslim.
Interrelation
Islam is the second largest religion as it has over 1.6 billion followers (Muslims).
Muslim is the subset of Islam.
Division
Islam is only one.
Muslims get divided further by sects and beliefs.
Islam and Muslim Definitions
Islam
A monotheistic religion characterized by the doctrine of absolute submission to God and by reverence for Muhammad as the chief and last prophet of God.
Muslim
Also Mos·lem (mŏzləm, mŏs-) A believer in or adherent of Islam.
Islam
The people or nations that practice Islam; the Muslim world.
Muslim
A member of the Nation of Islam; a Black Muslim.
Islam
The civilization developed by the Muslim world.
Islam
The religion of the Mohammedans; Mohammedanism; Islamism. Their formula of faith is: There is no God but Allah, and Mohammed is his prophet.
Muslim
A believer or follower of Islam
Islam
The whole body of Mohammedans, or the countries which they occupy.
Muslim
Of or relating to or supporting Islamism;
Islamic art
Islam
The religion of Muslims collectively which governs their civilization and way of life; the predominant religion of northern Africa, the Middle East, Pakistan and Indonesia
Islam
The monotheistic religion of Muslims founded in Arabia in the 7th century and based on the teachings of Muhammad as laid down in the Koran;
The term Muhammadanism is offensive to Muslims who believe that Allah, not Muhammad, founded their religion
What is Islam?
Islam is the second most popular religion in the world with possessing over 1.6 Billion followers across the globe. The Christianity is the only religion which holds more number of followers as compared to the Islam. But according to the latest reliable study, the way Islam is flourishing, it will overtake Christianity as the most popular religion in the world by 2070. The religion Islam is based on the individual’s submission to good and to obedience his law and not to do what is abided. Over the years, Islam was seen as the peaceful religion as it even asserted on behaving well with the enemies. The other salient features which make this religion prominent among other religions of the world is the message of equality regardless of color or race, women’s right of inheritance, and the urge to its follower to get educate themselves and also others. Although, nowadays some handpicked organization are portraying a negative image of Islam. Out of them, ISIS and Taliban are the prominent organization, which are tarnishing the image of Islam to the highest level.
What is Muslim?
The person accepting and practicing Islam is known as the Muslim. In other words, we can say that Muslims is the subset of set Islam in the case of Islam-Muslim relation. The person gives submission to the will of ALLAH and does obediently what he is obliged to do, whereas restrains himself from doing which is prohibited in the religion. If one wants to enter the religion Islam, he/she needs to believe and declare that ‘there is no God apart from ALLAH and Muhammad is the Messenger of God’,. It should be kept noted that one willing to become the good Muslim needs to follow the five pillars of Islam, and also need to follow the paths of the Last Prophet of Islam Muhammad PBUH. Shahadah, Salat (prayers), Zakat (charity), Fasting and visit to Holy Kabaah are the five pillars of Islam. The Muslims are further divided into dozens of sects, primarily there are two sects of Muslims, one is Shia, and the other is Sunni. All the sects have the similar basic belief like following the teachings of Quran, the oneness of ALLAH, and Muhammad PBUH as the last prophet.