Literally, “to fit as tightly as a chip (metaphorically a thin, close cut) against the ass”. This idiom is relatively recent in the Icelandic language with the oldest example in the Orðabók Háskólans's (“the University Dictionary”) ritmálssafn (“corpus of written language”) dating from the early 19th century from Guðmundur Jónsson's málsháttaasafn (“corpus of idioms”).