The name Finnigan is a boy's name of Irish origin meaning "fair". Finnigan and is often added to lists like If You Like Finn, You Might Love... and discussed in our forums with posts like "A brother or sister for little Jack or Olivia".
From the experts:
Finnigan is another way to spell Finnegan, one of the energetic Irish surname-names in vogue now. One note: While Finnigan, Finnian, Finley and so on are appealing names on their own, you don't need to use a longer form to get to Finn, which is a perfectly proper name all on its own.