The equivalent of God in Arabic is ILAH.

Let me show you.

Let's start with the Semitic root word EL (Alef-Lamed, Strong#0410).
It means 'mighty one' where it can be applied to ruler, judge, or god,but it is most common to translate in other language as god.Because languages are dynamic, the simple root word EL got itsemphatic form and eventually prolonged to ALEF-LAMED-HE.

Now we have Hebrew, Aramaic and Arabic among the Semitic languages family that still used today. Since they derived from the same Semitic root, let's see how this ALEF-LAMED-HE is pronounced in each language.

In Hebrew, we have it pronounced as ELOH (Alef-Lamed-He, Strong#0433). This word was sometimes written as ELOAH (Alef-Lamed-Waw-He). The plural form of ELOH is the widely-used ELOHIM (Alef-Lamed-He-Yud-Mem, Strong#0430).
These are the words that are used in the Bible.

The Bible also contains small portion that was written in ancient Aramaic. Here we found the usage of the Aramaic word ELAH (Alef-Lamed-He, Strong#0426) which is the exact cognate word of Hebrew's ELOH. They are actually the same word, spelled exactly with the same letters.

Another equivalent word of ELOH in Aramaic can be found in Peshita. In the Peshita, which is written in late Aramaic, they used ALAHA (Alef-Lamed-He-Alef).

Now what is the equivalent word for this Semitic ALEF-LAMED-HE in Arabic?

Yes, it is actually still the same word. In Arabic Alef-Lamed-He is pronounced ILAH or ILAHI (with extra Alef at the ending as in Aramaic's ALAHA).

And now we can draw in a table the summary of the word ALEF-LAMED-HE.

HEBREW: ELOH
ARAMAIC: ELAH
ARABIC: ILAH

So the word God in Arabic is obviously ILAH or ILAHI, not ALLAH.
I live in Indonesia, the country who has the biggest Moslem population in the world. These Arabic words were also absorbed into Indonesia/Malay language's vocabulary, and they mean 'god' or 'divine'.

But what about the word ALLAH ?

The word ALLAH is not a common word or equivalent to the Semitic word ALEF-LAMED-HE. You have to observe that the word Allah has double LAMED.

ALLAH is the personal name of god who worshipped in Islam. And in fact, the name ALLAH was already widely used in Arab peninsula far far ago before the birth of Islam in sixth century. In pre-Islam era, ALLAH is the
name of the highest diety of Mecca people. He is the protector god of Mecca and was worshipped along with his daughters (female deity) Allat, Al-Uzza, and Manat.

Herodotus, the Greek historian from about 450 BC, tells us that the North Arabians had a god and goddess named Orotal and Alilat. Orotal is simply a corruption of Allah, or Allah Ta'al, Allah The Most High.

The evidence of this usage is also acknowledged by the Moslem scholars although now they said Muhammad has redefined the meaning. According to this new definition, ALLAH is no longer the pagan idol but also the god that was worshipped by Abraham and the people of the book
(Jews and Nazarenes).

The best example to show the usage of ALLAH as personal name is in Islam syahadah or statement of faith "LA ILAH ILL ALLAH" which is translated"no god but Allah". ILAH is the Arabic word for god as demonstrated above.

Allah then is the personal name.