The word flaw ("imperfection") has contradictory roots. It's the first part which was most confusing: it had a myriad of meanings proposed by all my sources, including a "spark", a "piece of snow", and a "splinter". This is extraordinarily confusing to me at least because I can't figure out how all these fit together. Supposedly, all are imperfect somehow: a single "flake" of snow is out of place by itself, a "spark" is an inconvenience and an annoyance, and a "splinter" is obviously bothersome and detracts from the perfect smooth surface of wood. How these transitioned to become each other is also very strange. Anyway, somehow "splinter" became "slab" as we go further back to the Old Norse word flaga. This traces back to the Proto-Germanic word flago, also meaning "slab", which goes to Proto-Indo-European as plak, meaning "flat", since a slab is flat.
Adam Aleksic, a leading contender for valedictorian of his high school, is a 208-month-old boy with disturbing interests in etymology, vexillology, geography, and law. Adam would like to one day visit Tajikistan and just won an essay contest on linguistics!
The Etymology Nerd