pig

Concise Oxford English Dictionary © 2008 Oxford University Press:
pig/pɪɡ/

▶noun

• 1 an omnivorous domesticated hoofed mammal with sparse bristly hair and a flat snout, kept for its meat. [Sus domesticus.]

  ■ a wild animal related to this; a hog.

  [Family Suidae.]

  ■ N. Amer. a young pig; a piglet.

• 2 informal a greedy, dirty, or unpleasant person.

• 3 informal, derogatory a police officer.

• 4 an oblong mass of iron or lead from a smelting furnace.

• 5 a device which fits snugly inside an oil or gas pipeline and is sent through it to clean or test the inside, or to act as a barrier.

▶verb (pigs, pigging, pigged)

• 1 (often pig out) informal gorge oneself with food.

• 2 (often in phr. pig it) informal crowd together with others in disorderly or dirty conditions.

• 3 (of a sow) give birth to piglets; farrow.

• 4 operate a pig within an oil or gas pipeline.

– phrases
in a pig's eye informal, chiefly N. Amer. expressing scornful disbelief.
make a pig of oneself informal overeat.
make a pig's ear of Brit. informal handle ineptly.
on the pig's back Irish informal living a life of ease and luxury.
a pig in a poke something that is bought or accepted without first being seen or assessed.
pig in the python chiefly US a sharp statistical increase represented as a bulge in an otherwise level pattern, used especially with reference to the baby-boom generation regarded as having a gradual effect on consumer spending, society, etc. as they grow older. [from the shape of such an increase being likened to that of a pig swallowed by a python.]
a pig of a —— Brit. informal something unpleasant or difficult: I've had a pig of a day.

– derivatives
piglike adjective,
pigling noun.

– origin ME: prob. from the first element of OE picbrēd ‘acorn’, lit. ‘pig bread’ (i.e. food for pigs).