Insane/crazy

You also have the phenomenon which occurred after the Norman invasion, when a French/Latin word would be used alongside an Anglo-Saxon word. The most famous example of this is Cranmer's phrase, "We pray and beseech Thee", 'pray' being from French 'prier' (or the Norman-French equivalent) and 'beseech' from A.S. 'besecen', both meaning basically the same thing.

Then there are the pairs most famous in the culinary area, calf/veal, swine/pork, sheep/mutton, cow/beef etc.