mid-13c., ransaken, "to plunder; to make a search, search thoroughly," from a Scandinavian source akin to Old Norse rannsaka "to pillage," literally "search the house" (especially legally, for stolen goods), from rann "house," from Proto-Germanic *raznan (c.f. Gothic razn, Old English ærn "house;" Old English rægn "a plank, ceiling;" see barn) + saka "to search," related to Old Norse soekja "seek" (see seek).

Etymology [ edit] From Middle English ransaken, from Old Norse rannsaka, from rann (“house”) + saka (“search”); probably influenced by sack. Compare Danish ransage, Swedish rannsaka.

Ransack comes, via Middle English, from the Old Norse word rannsaka: the rann in rannsaka means “house”; the second half of rannsaka is what is known as an “ ablaut ” variant of sœkja, meaning “to seek, search out.”

Origin of ransack 1 First recorded in 1200–50; Middle English ransaken, from Old Norse rannsaka “to search, examine (for evidence of crime),” equivalent to rann “house” + saka, variant of sœkja “to search;” see seek)

ransack /ˈrænsæk/ vb (transitive) to search through every part of (a house, box, etc); examine thoroughly to plunder; pillage Etymology: 13th Century: from Old Norse rann house + saka to search, seek