Bly \b-ly\ as a boy's name is of Irish, Gaelic and Old Norse origin, and the meaning of Bly is "descendant of Blighe". Transferred use of the surname, an anglicized form of an Irish Gaelic name. Blighe is probably derived from Old Norse "Bl?", meaning "to gaze".

For more information, see also the related name Bligh.

Baby names that sound like Bly are Bayly, Baley, Baily, Bala, Balu, Bell, Bill, Byll, Billy and Bale. Other similar baby names are Aly, Bay, Ely and Sly.