bachelor
/ˈbætʃ.ə.lə(ɹ)/noun
A man who could marry but has not yet done so.
Now mostly survives in fixed phrases: bachelor's degree, bachelor party, bachelor pad. As a plain word for an unmarried man it sounds dated.
Related words
spinsterAn older woman who has never married, especially one considered past the usual age for marriage.widowerA man whose wife or spouse has died and who has not remarried; the male counterpart of a widow.nannyA person employed to look after a family's children.anniversaryThe date each year that marks an exact number of years since an important event took place.babysitterSomeone who looks after children for a short time while their parents or guardians are away.honeymoonThe holiday or stretch of time that a couple enjoys right after getting married.