Chastity - abstaining from sexual relations.
Source: Webster's Unabridged Dictionary 2nd Edition 1979
This is why there is a vow of celibacy and a vow of chastity.
The vow of celibacy applies only to Catholic clergy. There is a prohibition against fornication (all sexual contact between unmarried persons) applicable to all Catholics regardless of vocation.
I gave you the exact breakdown of the ways the terms “chastity” and “chaste” are used theologically.
That Webster cites a popular and limited use, one that I pointed out is common but misleading, is fine. Webster attempts to be descriptive of how words are used.
If you consult the Catechism of the Catholic Church, Thomas Aquinas, the Church Fathers etc. you’ll find that “chaste marital sexual relations” has a long and distinguished history.