A term for a certain degree of OCD. Examples of symptoms include:
-tendency to use hand sanitiser too much, to the point of taking baths in it.
-refusal to wear tampons, ever.
-generally attracted to guys named scott, jack, tyron etc.
-takes their siblings with them on dates
-laughs alot a jokes that aren't even that funny, ending up clapping like a retarded seal
-is the one person in the group of friends that everyone takes the piss out of

If you meet a 'Sciacca-lakka' keep them around for when you're feeling down, because making fun of them will make you feel better.