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3.
A person who is obnoxious and unattractive to the opposite sex.
I know. He is such a Hannigan.
by Un femme January 24, 2011
 
1.
An Irish name, it's the shortened Anglicized form of Gaelic Ó hAnnagáin ‘descendant of Annagán’, a pet form of the personal name Annach
Hello' my name is Keenan Hannigan.
by Scatman223 July 10, 2008
 
2.
super funtabulas guy who enjoies spelling things wrong and doing summersalts on yo face.
Oh my, look at that Hannigan do those funtabulas summersalts on yo face
by the hannigan February 05, 2009