An acquaintance is someone you know but are not close friends with. It's the individual you run into in the corridor or feel at ease meeting in a group context, but not generally alone yourself. A casual buddy is someone to whom you have a stronger emotional attachment. You are at ease meeting with this individual one-on-one. A friend is someone with whom you share all your secrets and who knows everything about you. You can trust them with your life. In other words, a friend is someone you feel comfortable sharing every aspect of your life with, while an acquaintance is someone you feel comfortable seeing occasionally but not always alone. While friends will often take an interest in what their acquaintances are doing, there are no hard and fast rules regarding friendships between non-friends. The only rule is that there must be some kind of mutual respect and acceptance for one another. Otherwise, you're just building walls around your heart that prevent it from being loved completely. And once those walls come down, you never really know anyone again. Acquaintances and friends have different requirements and expectations of them. An acquaintance would never expect you to give up any information about yourself or trust them with anything important. A friend would expect exactly that of their acquaintance. They would also expect their friend to be honest with them. Acquaintances cannot call each other by name, whereas friends use first names when they address each other.