Having Physical emotional connection with somebody:

Intimacy generally refers to the feeling of being in a close personal association and belonging together. 

Being in the state of being able to share one’s inner thoughts, desires, fears, dreams with the person you trust.

It is a familiar and very close affective connection with another as a result of a bond that is formed through knowledge and experience of the other. 

Genuine intimacy in human relationships requires dialogue, transparency, vulnerability, and reciprocity. 

The verb “intimate” means “to state or make known”. To bring one’s inner motives, fears, feelings of insecurity, passion, shame or secretes, bringing them from a hidden dark state, into the physical state of exposing them to the person you trust.

The activity of intimating (making known) underpins the meanings of “intimate” when used as a noun and adjective. The noun “intimate” means a person with whom one has a particularly close relationship.

The adjective “intimate” indicates detailed knowledge of a thing or person (e.g., “an intimate knowledge of engineering” and “an intimate relationship between two people”).

Research in the field of psychological and mental rehabilitation has proven that; people who have been abused, raped, cheated on, divorced, or children who have not had a fatherhood upbringing, will mentally build up walls of self defense in the limbic system or primitive part of the brain.

And thus; this will psychologically lead to the state of avoiding, hating or despising intimacy, some people do it consciously and some do it an consciously. 
Article by Conscious lifestyle…