From an Old French name, Raimund, of Germanic origin, from ragin ‘advice, decision’ + mund ‘protector’. This was adopted by the Normans and introduced by them to Britain. Subsequently it dropped out of use, but was revived in the middle of the 19th century, together with several other given names of Old English and Norman origin.
Czech: occupational name for a merchant or dealer, Czech soukup (from Slavic sou- ‘with’ + kup ‘buy’). The vocabulary word later acquired the sense ‘fence’, i.e. ‘one who receives stolen property or abets a thief’, but this is probably irrelevant to the surname, which was formed before this sense was established.