اللَّهُ الصَّمَد

Allah is Independent of aII and all are dependent on Him. (The Holy Quran, 112:2)

The word used in the original is صمَد (samad) of which the root is s-m-d. A look at the derivatives in Arabic from this root will show how comprehensive and vast this word is in meaning. (Lexical discussion of the meanings of the derivatives is omitted).
On the basis of these lexical meanings the explanations of the word as-Samad in the verse اللَّهُ الصَّمَد Allah-us-Samad, as reported from the Companions, their immediate successors and the later scholars are given below:

Hadrat 'AIi. 'Ikrimah and Ka'b Ahbar: "Samad is he who has no superior. "
Hadrat 'Abdullah bin Mas`ud, Hadrat `Abdullah bin `Abbas and Abu Wail Shaqiq bin Salamah: "The chieftain whose chieftancy is perfect and of the most extraordinary kind. "
Another view of Ibn 'Abbas: "Samad is he to whom the people turn when afflicted with a calamity." 
Yet, another of his view: "The chieftain who in his chieftaincy, in his nobility and glory, in his clemency and forbearance,. in his knowledge and wisdom is perfect. " 

Hadrat Abu Hurairah: "He who is independent of all and all others are dependent upon him. "

 أَحَد

The One and Only.

Fourteen hundred years ago, the polytheists and Jews in Arabia asked Prophet Muhammad (s.a.a.w.) questions about God. Some of these questions were:

Tell us of your Lord's ancestery.
O Muhammad, tell us attributes of your Lord, who has sent you as prophet.
What is your Lord made of?
Is He made of gold, silver, iron or what?
Does He belong to a race of Gods?
Does He have parents or children?
Who will inherit the earth after Him?

The answer came in the following verse of the Holy Quran:

قُلْ هُوَ اللَّهُ أَحَدٌ

Say: "He is Allah, the One and Only.” (The Holy Quran, Surah Al-Ikhlas, Ayah 1, 112:1)

Let us first analyze the sentence, “ Huwa-Allahu Ahad”,  هُوَ ٱللَّهُ أَحَدٌ   lexically.

In this sentence,  Huwa is the subject (mubtada) and Allahu its predicate (its khabar), and Ahad-un its second predicate (second khabar). According to this parsing the sentence means: "He (about Whom you are questioning me) is Allah, the One and Only.”  Another meaning according to the language rules can be, "He is AIIah, the One."

Here, the first thing to understand is the unusual use of AHAD in the sentence.

Generally, the word is either used in the possessive cases (mudhaf, mudhaf elaih) like yaum ul-ahad (first day of the week), fab’atho ahada kum (send one of your men)  or to indicate total negative (nafi ‘aam) as Ma jaa a-ni ahad-un (No one has come to me), or in common questions like Hal `indika ahad-un (Is there anyone with you?), or in conditional clauses like In ja'a-ka ahad-un (If someone comes to you), or in counting as ahad, ithnan, ahad ashar (one, two, eleven). Apart from these uses, there is no precedent in the pre-Qur'anic Arabic that the mere word ahad might have been used as an adjective for a person or thing. After the revelation of the Holy Qur'an, this word has been used only for the Being of Allah, and for no one else. This extraordinary use by itself shows that being single, unique and matchless is a fundamental attribute of Allah; no one else in the world is qualified with this quality: He is One, He has no equal.