The Old Improbable Island Wiki

Adjective: furtive, deceitful, unfair, or sly.¹⁾

It is also a defining characteristic of certain bastards that inhabit Improbable Island. Should you meet a sneaky person, place, or object²⁾³⁾, the only option is to run screaming into the night⁴⁾

¹⁾

Also rumored to sometimes be used to describe something that is impossible to kill.

²⁾

Especially if it's a sneakily moving box.

³⁾

and even more especially if a big question mark or exclamation point appears over your head when you go to examine said box.

⁴⁾

Unless it's day, in which case you're screwed.