[Old English -uc, -oc.]
This suffix is now only historical. In some cases it had a diminutive sense, but that has largely been lost—the only one remaining is hillock, a small hill. Other examples are buttock, originally a small butt, in the sense of backside, and bullock, literally little bull, a castrated male animal raised for beef. Several terms for animals may originally have been diminutives, though the evidence is unclear: dunnock, the hedge sparrow, perhaps ‘the little dun-coloured (bird)’, and haddock and pollock, two species of fish. Two British dismissive slang terms may include it, though their origins are uncertain: slummock, a dirty, untidy, or slovenly person; wazzock, a stupid or annoying person. Pillock, however, probably derives from pillicock, an old name for the penis. Other words in this ending come from a variety of sources, seemingly unconnected either with the suffix or each other: bannock, a round, flat loaf; futtock, each of the middle timbers of a ship's frame; hassock, a cushion for kneeling on in church; hammock comes through Spanish from Taino hamaka with the ending altered in imitation of -ock.