reaver n.

Middle English reven "to rob plunder," from Old English reafian "to rob (something from someone), plunder, pillage, take away by force or stealth," from Proto-Germanic *raubōjanan "to rob, deprive of" (source also of Old Frisian ravia, Middle Dutch roven, Dutch rooven, Old High German roubon, German rauben), from PIE *runp- "to break" (see corrupt (adj.)).

Related: Reaved; reaving. Now obsolete or archaic or dialectal only. The old past participle was reft. Also compare bereave. OED reports that the forms reive, rieve, originally Scottish, were sometimes used "when the reference is to the taking of goods or cattle by force," hence reiver, reiver, etc., e.g. "The Reivers," Faulkner's novel.

"sea-robber, pirate," late 14c. (c. 1300 as a surname), from Middle Dutch rover "robber, predator, plunderer," especially in zeerovere "pirate," literally "sea-robber," from roven "to rob," from Middle Dutch roof "spoil, plunder," related to Old English reaf "spoil, plunder," reafian "to reave" (see reave (v.), and compare reaver).