From the French form of the Latin name Valeria, feminine of Valerius, an old Roman family name apparently derived from valere ‘to be healthy, strong’. The name owes its popularity as a male name in France to the cult of a 3rd-century saint who was converted to Christianity by Martial of Limoges. The masculine form Valery is found occasionally in England in the 16th century, but by the 17th century had fallen into disuse.
German (also Kräft), Danish, Swedish, and Jewish (Ashkenazic): nickname for a strong man, from Old High German kraft, German Kraft ‘strength’, ‘power’. The Swedish name probably originated as a soldier's name. In part the German and Danish names possibly also derive from a late survival of the same word used as a byname, Old High German Chraft(o), Old Norse Kraptr.