N. This describes when one does not wipe (in going to the bathroom) properly, and thus infestations of what was to be wiped are now pushed under the poor sap’s fingernail(s). (This term was begun by Artie Lange of the Howard Stern Show.)
“Yo Bill what’s that under your fingernail? You stupid ass, can’t you wipe yourself? Now you’ve got shitnail.”
Shit + Tsunami= Shitnami. An urgent, sudden, copious, and explosive emptying of bowel contents. Often happens after a night of draft beer, boiled eggs and/or White Castles.