1 definition by densie

nicknamed originating from ireland or scotland. a person who inherently fails at everything he or she sets out to accomplish in life, masking his or her mediocrity with a noticeably forced display of nonchalance and happiness whilst in public, donning the plastic and somewhat smug characteristic some describe as the 'perma-smile'.

in more intimate settings, the alone 'sheamus' can be found whimpering in fetal position over the inescapable reality of his or her repressed sadness, often located weeping in front of mirrors or in the shower.
friend 1: man, tom sure is always happy!

friend 2: yeah, because he's a sheamus, dude. my dorm walls are paper thin, his loud sobbing at night always keeps me up.
by densie June 22, 2009
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