Celibacy is a personal commitment to avoiding sexual relations, in particular a vow from marriage

Marriage

Marriage is a social union or legal contract between people that creates kinship. It is an institution in which interpersonal relationships, usually intimate and sexual, are acknowledged in a variety of ways, depending on the culture or subculture in which it is found...

. Typically celibacy involves avoiding all romantic relationships of any kind. An individual may choose celibacy for religious reasons, such as is the case for priest

Priest

A priest is a person authorized to perform the sacred rites of a religion, especially as a mediatory agent between humans and deities. They also have the authority or power to administer religious rites; in particular, rites of sacrifice to, and propitiation of, a deity or deities...

s in some religions, for reasons of personal development and self-discovery, or for many other reasons. Historically many cultures have venerated celibacy in certain individuals seeing the commitment as a form of discipline to be admired.

Though the term celibacy can sometimes be used to refer simply to being unmarried, this usage is not common today.
The English word celibacy derives from the Latin , meaning "unmarried".