Medieval variant of Mervyn, resulting from the regular Middle English change of -er- to -ar-. Modern use may represent a transferred use of the surname derived from this in the Middle Ages. It is popular in the United States, where it is associated in particular with the American singer Marvin Gaye (1939–84) and the boxer Marvin Hagler (b. 1954).
German: 1. occupational name for a fisherman, from Middle High German keiper ‘fisherman’, ‘fish netter’, found in the Upper German dialects, but also in Prussian, keip ‘weir’ (fish trap) (see Keip) may be the source of the name. 2. variant of Keuper, itself a variant of Käufer (see Kaufer) or of Küpper (see Kupper); this is a frequent surname in the lower Rhine area.