A bachelor is the male version of the spinster. A spinster is an unmarried woman who is likely to remain single, and a bachelor is a man who has never been married and may or may not want to be wedded in the future.
Although the two terms are roughly equivalent, "spinster" and "bachelor" do not always carry the same social connotations. A spinster is usually an older woman who has never found or wanted a spouse, whereas bachelors tend to refer to single men of any age who have not yet married. For this reason, some men who choose to remain unmarried throughout their lives prefer the terms "lifelong bachelor" or "confirmed bachelor" to signify their choice to remain single, while those seeking marriage may choose to use the term "eligible bachelor."