The name Declan is of Irish origin and means "Full Of Goodness." The origin is the culture in which the name originated, or in the case of a word--the language in which it most appears.
Common nicknames for the name Declan include Dec and Dee. Famous people with the name Declan tend to be of Irish descent. Athletes include Declan Kidney, Declan Meehan, and Declan O’Sullivan. Musicians include Declan Affley and Declan deBarra. Declan is the real first name of musician Elvis Costello. Saint Declán of Ardmore was an early Irish saint of the Déisi Muman, who was remembered for having founded the monastery of Ardmore in what is now County Waterford in Ireland. Fictional Declans include Declan Coyne from the television show Degrassi: the Next Generation.