intimate

having or fostering a warm or friendly and informal atmosphere

“an intimate cocktail lounge”

marked by close acquaintance, association, or familiarity

“intimate friend”

used euphemistically to refer to the genitals

“he touched her intimate parts”

having mutual interests or affections; of established friendship

“pretending she is on an intimate footing with those she slanders”

imply as a possibility

concerning things deeply private and personal

“intimate correspondence”

involved in a sexual relationship

“the intimate (or sexual) relations between husband and wife”

give to understand

thoroughly acquainted through study or experience

“this girl, so intimate with nature”

innermost or essential

“the intimate structure of matter”