The meaning of Intimacy varies from relationship to relationship, and within a given relationship. Intimacy has more to do with shared moments than sexual interactions. Intimate feelings may be connected or confused with sexual arousal. Intimacy is linked with feelings of closeness, safety, trust and transparency among partners in a collaborative relationship.
For intimacy to be sustainable and nourishing it also requires trust, transparency and rituals of connection. It is possible to compete over intimacy but that is likely to be self-defeating. Intimacy requires empathy - the ability to stand in the other's shoes.
Intimacy is both the ability and the choice to be close, loving and vulnerable - with yourself in the first instance. Intimacy requires identity development. You have to know yourself and your innards in order to share your self with another. Knowing yourself makes it possible to stand for yourself in an intimate relationship without taking over the other or losing yourself to the other.
This ability to be separate and together in an intimate relationship and being okay with that is called self-differentiation. See more on this subject in Murray Bowen. Lacking the ability to differentiate one self from the other is a form of symbiosis. This too is different from intimacy though to some that kind of dependent closeness may feel the same.
From that centre of self knowledge and self differentiation intimate behaviour joins us with family, close friends as well as those with whom we are in love. It dwells in a reciprocity, which builds on self-disclosure and candour.
The main forms of intimacy are emotional intimacy and physical intimacy. Intellectual intimacy, familiarity with a person's culture and interests, is common among friends. Members of religious or philosophic groups may also perceive a "spiritual intimacy" in their commonality. Some describe intimacy with the homonymous "into me see".
Intimacy can also be identified as knowing someone in depth, knowing many different aspects of a person or knowing how they would respond in different situations, because of the many experiences you've shared with them.
Some lose themselves in the first flush of love. 'Falling in love' is a little different from intimacy per se. Some are engulfed by their families in a way that is not close or intimate even though it is described that way by those who are consumed by their family. The first flush of love can be like that too, but slowly the individual will assert themselves and this test the willingness of both to be intimate.
This is not a precise definition but even without being specific, it seems that intimacy and healthy relationships go hand in hand. Indeed, intimacy is a basic ingredient in any meaningful relationship: the basis of friendship and one of the foundations of love.
Poor development of intimacy can lead to getting too close too quickly; struggling to find the boundary and to sustain connection; being poorly skilled as a friend, rejecting self-disclosure or even rejecting friendships and those who have them.
It is worth distinguishing intimate relationships from strategic relationships. Intimate behaviour occurs in the latter but it is governed by a higher order strategy, of which the other person may not be aware. For example getting close to someone in order to get something from them or give them something. That 'something' might not be offered so freely if it did not appear to be an intimate exchange and if the ultimate strategy had been visible at the outset.
Secrets are generally hostile to intimacy in a committed relationship, but not knowing of the existence of a secret, one can continue to believe there is intimacy. Maintaining the illusion of intimacy may be a strategic skill where there is an imbalance of power brought about by the existence of a secret. Knowledge is the currency of power.
Betrayal of intimacy can be a traumatic experience. The person can feel cheated as well as humiliated, experiencing themselves being a sucker or fool.