From a surname which was originally a shortened form of various Gaelic surnames beginning with Mac or Mc (from Gaelic mac meaning "son"). It is also used as a generic slang term for a man.
Origin of the name Maxwell: Transferred use of the Scottish surname originating from a place-name derived from the name Maccus (great) and the Old English wielle (spring, pool) or wella (stream). The name was indicative of one who dwelled at Maccus' spring or the stream of Maccus.