Brahman and Brahmin can confuse anyone, since this is most common confusion, because of almost similar spelling, Let me explain it one by one. Brahman -- Brahman (Sanskrit: ब्रह्मन् "the Supreme Being; the Absolute Reality; Godhead"), from the verb brh, "to grow", and connotes "immensity" — is the impersonal and immanent, infinite cause and support of the universe that has no form or attributes. The uncaused cause of the Universe; satchidānanda (Existence-Consciousness-Bliss Absolute), The Eternal Changeless Reality, not conditioned by time, space and causation. Brahman is the basis, source and support of everything — the transcendent reality which is the Divine Ground of all matter, energy, time, space, being, and everything beyond in this universe. Its nature consists of the three incommunicable attributes of (1) sat (Absolute Being), (2) chit (Consciousness), (3) ananda (Bliss). This Supreme Being assumes a dual nature — Male and Female. The male aspect is known as Purusha which means “that-which-fills” — and the Female aspect is known as Shakti which translates as “Energy” or “Dynamic Force” or Prakriti — material nature. Also called as Paramātman (Universal Self), Parasiva, Ultimate Reality, Supreme Being or the Absolute. Brahma-- (Sanskrit: ब्रह्मा )Brahma is the God of Creation and He is attributed to the creation of the brahmãnd (entire universe) and the life forms within it. The manifested world of plurality has emerged from the unmanifest Reality. To indicate this Brahma the creator is described as being born from the kamala — lotus springing from Vishnu's nabhi (navel) as he is lying on the great serpent, Ananta in the milky ocean. Hence, his names Nabhija (navel born), Kanja (water born). According to Manu Smriti, the self-existent Lord manifested to dispel the darkness enveloping universe. He created the waters and deposited a seed that became a golden egg from which he was born as Brahma. He divided the egg into two parts to construct the heaven and earth, and created the ten Prajapatis, mind-born sons, who completed the work of creation. Brahma, the infinite, the source of all space, time, causation, names and forms, has many interesting and instructive designations. Theologically, he is the eka aksharam (single letter) AUM, and the svayambhu (uncreated creator), the self-born first person. Philosophically, he is the first manifestation of one's existence — ahankara. Cosmologically, he is hiranya garbha (golden embryo), the ball of fire, from which the universe develops. He is Prajapati, since all creatures are his progeny. He is pitamaha (patriarch), vidhi (ordinator), lokesha (master of the universe), dhatru (sustainer) and Viswakarma (architect of the world). Brahmin -- ( Sanskrit ब्राह्मण ) Brahman, Brahmin, and Brahma have different meanings. Brahman refers to the Supreme Self. Brahmin (or Brahmana) refers to an individual, while the word Brahma refers to the creative aspect of the universal consciousness. Brahmin are teacher and priest of society. Now, who is Brahmin : He (indeed) who, after having all his desires fulfilled as a result of perceiving (realizing) directly, as an amalaka fruit in one’s hand…. The Atman that is One without a second (or is beyond compare), (That is) bereft of (distinctions of) clan and (is not composed of) the constituents of Prakriti (guNa-hInaM), and actionless, (That is) free of all defects like the six infirmities (viz. old age, death, sorrow, delusion, hunger and thirst) and the six states of existence/transformations (viz. birth, existence, growth/development, transformation, waning and perishing), (That is) of the nature of Immutable Reality, of Consciousness, Blissful and Infinite/Eternal, (That is) an Independent Entity (not deriving its existence and properties from anything else), (That is) devoid of determinations, but (itself) the support of infinite determinations, (That is) present in all living and non-living beings as the immanent Soul, (Who) pervades the interior and envelopes the exterior of everything as ether, (That is) possesses the attribute of perfect and complete (akhanda) Bliss, (That is) incomparable, (That is) known only through one’s own (spiritual) experience (and not through reading of books or teaching by others) and is inferred only indirectly (because of It cannot be perceived by the senses); Becomes free of the defects of desire, attachment and the like, Becomes endowed with the (positive) qualities like tranquility etc., becomes free of (negative) behaviors like jealousy, greed, expectations, delusion etc., and leads a life in which the mind is not tainted pretensions, ego and the like. He alone, who possesses the aforementioned characteristics, is a Brahmin- such is (indeed) the import of Sruti, Smriti, Itihasa and the Puranas. From VajraSuchika Upanishad
