Colloquial terms

A number of colloquial terms have been used to describe friendship and the context in which a friendship is fostered. These are briefly described below.

* A friend who supports others only when it is easy and convenient to do so is called a "fair-weather friend".
* A friend who supports their own friends through emotional difficulties is a "true friend." This term also denotes a large degree of altruism, in that the true friend often sacrifices something of his or her own (usually their time and resources) in order to help the friend in need. True friends also are known to be very rare. A true friend may not be your best friend but someone who you know will be there for you.
* Friends who are sexually intimate but don't consider themselves to be dating is said to be a "casual relationship". This is also referred to as being "friends with benefits".
* A "best friend" is a friend to whom one feels closest. It is usually implied that the relationship is reciprocal, but such is not always the case, and best friend relationships can often be very complex.