A couple of excerpts from the Wikipedia entry on Celibacy:
1 The English word celibacy derives from the Latin caelibatus, "state of being unmarried", from Latin caelebs, meaning "unmarried".
2 A. W. Richard Sipe, while focusing on the topic of celibacy in Catholicism, states that "the most commonly assumed definition of celibate is simply an unmarried or single person, and celibacy is perceived as synonymous with sexual abstinence or restraint."[14] Sipe adds that even in the relatively uniform milieu of Catholic priests in the United States "there is simply no clear operational definition of celibacy".
In French celibataire means unmarried.
To the best of my knowledge, the Bishop of Grantham has not married his partner. He is thus celibate.
In the RC church, until about the 11th and 12th centuries, priests were married. The rule of celibacy was introduced to protect church property from being inherited by the children of priests.