Neil m
Irish, Scottish, and English: Anglicized form of the enduringly popular Gaelic name Niall. Its derivation is disputed, and it may mean ‘cloud’, ‘passionate’, or perhaps ‘champion’. It was adopted by the Scandinavians in the form Njal and soon became very popular among them. From the Middle Ages onwards, this name was found mainly in Ireland and the English-Scottish Border region. However, in the 20th century it has spread to enjoy great popularity in all parts of the English-speaking world.
Pet form: Scottish (Highland): Neillie.
Feminine form: Scottish (Highland): Neilina.
First names dictionary. 2012.