Manly is an uncommon given name of English origin, derived from Middle English 'manlike'. It means "resembling a man" or "having qualities characteristic of men". This name was more popular in the 19th century but has since become quite rare.
"The name Manly experienced periods of popularity and decline over time, with a significant peak in the years leading up to World War I, particularly between 1913 and 1919. However, it has since become quite rare, with only five births recorded annually in recent years (1880, 1881, 1892, 1895, 1966)."