ego

(Latin: I [first person, singular pronoun])

Don't confuse this ego with another aego-, ego- which means "goat".

alter ego
1. Another side of oneself; a second self; another aspect of one's self: "The characters Dr. Jekyll and Mr. Hyde were alter egos in a literary tale of horror."
2. An intimate friend or a constant companion; an inseparable friend.
3. A very close and trusted friend who seems almost a part of yourself.
4. A second self; a perfect substitute or deputy: "His assistant manager acts as his alter ego when he is not in the office."
alteregoism
1. Identification with people of similar personality to one's own.
2. Interest and sympathy for people who are in the same situation as, or are otherwise, similar to one's self.
ego
1. The self, especially as distinct from the world and other selves.
2. In psychoanalysis, the division of the psyche that is conscious, most immediately controls thought and behavior, and is most in touch with external reality.
3. An exaggerated sense of self-importance; conceit.
4. Appropriate pride in oneself; self-esteem.
5. Consciousness of one's own identity.

In psychoanalytic theory, the division of the psyche that is conscious, most immediately controls thought and behavior, and mediates between the person and external reality.

None are so empty as those who are full of themselves.
—Benjamin Whichcote
Ego spem pretio non emo.
I don't buy hope for a price.

Written to currently mean: "Show me" or "I won't buy a pig in a poke (bag or sack)."

Ego sum rex Romanus (imperator Romanorum) et super grannaticam.
Translation: "I am the king of Rome and above grammar."

Words spoken by the Holy Roman Emperor Sigismund at the Council of Constance (1414-1418) when a cardinal corrected his Latin.

ego trip, ego-trip
1. A course of action or an experience that boosts someone's sense of his or her own importance; a slang term.
2. An act, experience, or course of behavior that gratifies the ego.
egocentric, egocentricity
1. Holding the view that the ego is the center, object, and norm of all experience.
2. Confined in attitude or interest to one's own needs or affairs.
3. Caring only about oneself; selfish.
4. Marked by extreme concentration of attention upon oneself; self-centered.
5. Limited in outlook or concern for one's own activities or needs
egocentrism
1. Regarding oneself and one's own opinions or interests as most important.
2. Attempting to get personal recognition for oneself (especially by unacceptable means).
egodystonic
1. In psychology, of or relating to ideas, behaviors, or impulses that are unacceptable to the ego or self.
2. Pertaining to something repulsive to the individual's self-image.
egoism
1. The ethical doctrine that morality has its foundations in self-interest.
2. The ethical belief that self-interest is the just and proper motive for all human conduct.
3. Excessive preoccupation with one's own well-being and interests, usually accompanied by an inflated sense of self-importance.
4. Egotism; conceit.

Synonyms: conceit, egotism, narcissism, vanity. These nouns denote excessive high regard for oneself: boasting that reveals conceit; imperturbable egoism; narcissism that shuts out everyone else.

egoist
1. Someone who is devoted to one's own interests and advancement; an egocentric person.
2. An egotist.
3. An adherent of egoism.
egomania
1. An intense and irresistible love for oneself and concern just for one's own needs.
2. An extreme self-centeredness or self-appreciation.
3. An abnormal interest in one's self.
One nice thing about egotists:
They don't talk about other people.
—Lucille S. Harper
Egomaniacs are always me-deep in conversation and when two of them meet, it becomes a case of an I for an I.
—Anonymous
egomania, egomaniac
1. A morbid egotism; an extreme self-centeredness or self-appreciation.
2. An abnormal interest in one’s self; extreme egotism.
egomaniac
1. An abnormally egotistically self-centered person.
2. A person who considers himself/herself to be extremely important and able to do anything that she/he wants to do.
egopathy
Hostile behavior due to a psychopathically exaggerated sense of self-importance. Egopathic patients are characterized by a strong egocentric trend that compels them to deprecate others in their constant aggressive and unconceding attitude.