The word “Allah” which is translated into God is a particular and the most comprehensive of God’s names. This name is used only for God because each name of the Lord, the Almighty, reflects a single attribute of God. It is the only name that combines and includes all the attributes of divine perfection. In other words, “Allah” incorporates all the features of glory and beauty.
“Allah is derived from the root “valah” which means perplexity, because the mind is perplexed when it tries to understand the divine essence.
The Commander of the Faithful, Ali (a.s.) has been reported as having said:
“Allah means the worshipped one, by Whom people are bewildered, and to Whom they are submissive. Allah is the One veiled from the grasp of sights, and the One hidden from imagination and contemplation.”
Some have said that “Allah” is derived from “Alah (worship) and it is from the root word “al-Ilah” which means the only (righteously) worshipped (deity). God’s other names are often used to refer to one of the attributes of Allah. For example, “Ghafoor” and “Rahim” refer to God’s compassion and mercy:
“فَإِنَّ اللَّهَ غَفُورٌ رَحِیمٌ”.
“Allah is surely Forgiving, Merciful.”
The attribute “Sami'” refers to God’s knowledge of what is heard and “Alim” refers to His knowledge of everything:
“فَإِنَّ اللَّهَ سَمِیعٌ عَلِیمٌ”
“Allah is surely Hearing, Knowing.”
“Basir” signifies His knowledge of those things that are seen.
“وَ اللَّهُ بَصِیرٌ بِما تَعْمَلُونَ”
“And Allah is Seer of what ye do.”
“Razzaq” (Bestower of Sustenance) refers to God’s sustaining of all the creatures. “Zulquwah” refers to His power and “Matin” to His being strong:
“إِنَّ اللَّهَ هُوَ الرَّزَّاقُ ذُو الْقُوَّةِ الْمَتِینُ”
“Surely Allah is the Bestower of sustenance, the Lord of Power, the Strong.”
Finally “Khaliq” (Creator) and “Bari'” (Evolver) refer to God’s creation and “Musawir” indicates His bestowing of “forms”:
“ُوَ اللَّهُ الْخالِقُ الْبارِئُ الْمُصَوِّرُ لَهُ الْأَسْماءُ الْحُسْنى”
“He is Allah, the Creator, the Evolver, the Bestower of Forms (or Colours). To Him belongs the Most Beautiful Names.”
In fact, it is only “Allah” which is God’s most comprehensive name. It is for the same reason that many attributes in a single verse qualifies the name “Allah”:
“ُوَ اللَّهُ الَّذِی لا إِلهَ إِلَّا هُوَ الْمَلِکُ الْقُدُّوسُ السَّلامُ الْمُؤْمِنُ الْمُهَیْمِنُ الْعَزِیزُ الْجَبَّارُ الْمُتَکَبِّر” سُبْحَانَ اللَّهِ عَمَّا یُشْرِکُونَ.
“Allah is He, than Whom there is no other god;- the Sovereign, the Holy One, the Source of Peace (and Perfection), the Guardian of Faith, the Preserver of Safety, the Exalted in Might, the Irresistible, the Supreme: Glory to Allah! (High is He) above the partners they attribute to Him.”
One of the clear proofs showing the comprehensiveness of this name is that expressing faith and belief is possible only through the sentence “La ilaha illallah” (There is no deity but Allah). Therefore, sentences like “There is no deity but the Knowledgeable”, “but the Creator” or “but the Sustainer” and the likes cannot incorporate and corporate monotheism and Islam. It is for the same reason that when other religions speak of the “worshipped deity” of Muslims, they use the name “Allah” because describing God by “Allah” is particular to Muslims.
 – Tafsir Namunah, vol.1, pg. 21 and 22
 – Behar al-Answar
 – Al-Baqarah: 226
 – Al-Baqarah: 227
 – Hujurat: 18
 – Al-Dhariyat: 58
 – Al-Hashr:24
 – Al-Hashr: 23