Probably a reduced or altered form of Morfield or Murfield; see Merrifield, a name found in various spellings in Cornwall, Devon, Wilts, Hants, Sussex, Surrey, and Kent. This is perhaps the most likely source of the earliest examples in S and SW England, but see (ii) for another source which seems to have arisen from the late 17th century onwards, leading to possible confusion between names originally with -field and those originally with -foot. Compare the Stepney and the Saint Giles Cripplegate examples cited below with Susan Morefield 1611, Richard Morefield 1647, David Morfoot 1681 in IGI (Stepney, Middx), and Thomas Morefield 1673 in IGI (Saint Giles Cripplegate, London), although these could be different family names coinciding in the same parishes.
With the Suffolk examples of Morphew, etc., compare John Morfull 1547 in IGI (Woodbridge, Suffolk), which is a variant of Morfett (see Moorfoot). In Sussex and Kent, this is illustrated by Dennis Morefoote 1551, Sarah Morfet 1696, Thomas Morfey 1759 in IGI (Wartling, Sussex); Thomas Morfoot 1672, Thomas Morfee 1700, Thomas Morfett 1734, Zabulon Morphey 1745 in IGI (Hastings, Sussex); Elizabeth Morfett 1745, Jeremiah Morphett 1758, John Morphey 1798 in IGI (Cranbrook, Kent); Thos. Morfew 1747, Thomas Morfet 1755, Thomas Morfey 1750 in IGI (Guestling, Sussex).
A similar pattern of variation occurs in Norfolk: Walter Morefoote 1626, James Murfee 1687, Alexander Morfee 1701, Mary Morfew 1775 in IGI (Great Yarmouth, Norfolk). There is early modern evidence for Murph(e)y as a variant of Morphey, but 18th-century bearers listed below could alternatively belong with (iv). Improbably from Anglo-Norman French morphé, Middle English morphé, morfe(e), morfeu, morpheu, murfue, meaning ‘morphea, any one of a group of skin diseases characterized by discoloration of the skin and scurfy eruptions’. This is a medical term rather than an item of ordinary vocabulary from which a medieval nickname and surname might naturally have derived, and the absence of corresponding medieval surname forms adds to the doubtfulness of such an origin.
However, the word was still current in early modern England and may have played a part in the alteration of the names in (i) and (ii) to Morphey and Morphew through learned folk etymology. See Irish Murphy.