Simply stated, a Manmukh is an ego-centric person whose actions are controlled by the following urges and desires: lust, anger, greed, material attachment, self-conceit, envy and stubborn mindedness, with their numerous variations.
Thus, a Manmukh regardless of how advanced he may be in his or her material qualifications by education or cultural status, lacks in Divine qualities; consequently, is not aware of the Cosmic Reality that is contained within him/her.
Such individuals fail to attain Spiritual Perfection or Intuitive Understanding of the "ultimate reality"; for their intellect is dimmed by material contamination.
Sikhs believe that in order to make us aware of Manmukhs and their conduct, Gurbani has provided them with numerous symptoms of such material beings caught in the vertex of unenlightened existence.
Some of these symptoms include: egoism, ignorance, selfishness, duality, bondage, evil-mindedness, falsehood, violence, untruthfulness, doubts, superstitions, uncontrolled senses, identification with the feeling of "I, me, mine, your", lust, anger, greed, attachment, self pride, self-conceit; superstitious, jealousy and enviousness, stubborn mindedness, hatred, fanaticism, conflicts, lack of contentment, material hankering and lamentation, lack of mental control and inner peace, self-centredness, are full of quarrel and contentions, always interested in taking instead of giving, love for material world instead of the Self within, eating, lying, plundering, and animosity.
Opposite to these are the attributes of Gurmukhs (Spiritual Beings) According to the Gurbani, a Manmukh is not a question of heredity, family of birth, ancestry, race, region, social status, caste, creed, education, titles, religion or any peculiar external appearance of a person; it is a question of lack of Naam Simran, self-evaluation, unenlightened existence, cynicism, egoism, ignorance, hypocrisy, bondage, mental delusion, body-consciousness, mistaken identity, and so on.
Below are several quotations from the Holy Text: From Sri Guru Granth Sahib: ਗੁਰਮੁਖਿ ਲਾਧਾ ਮਨਮੁਖਿ ਗਵਾਇਆ ॥ The Gurmukhs obtain it, and the self-willed manmukhs lose it.