to search thoroughly or vigorously through (a house, receptacle, etc.): They ransacked the house for the missing letter.
2.
to search through for plunder; pillage: The enemy ransacked the entire town.
Origin: 1200–50; Middle English ransaken < Old Norse rannsaka to search, examine (for evidence of crime), equivalent to rann house + saka search (variant of soekja to seek)
mid-13c., from O.N. rannsaka "to pillage," lit. "search the house" (especially legally, for stolen goods), from rann "house," from P.Gmc. *rasnan (c.f. Goth. razn, O.E. ærn "house") + saka "to search," related to O.N. soekja "seek" (see seek). Sense influenced by sack (v.).