groin

Etymology 1

From earlier grine, from Middle English grinde, grynde, from Old English grynde (“abyss”) (perhaps also "depression, hollow"), probably related to Proto-Germanic *grunduz; see ground. Later altered under the influence of loin.

noun

1. The crease or depression of the human body at the junction of the trunk and the thigh, together with the surrounding region.
   The Mexican levelled nine minutes from time after Steven Gerrard, making his first start since undergoing groin surgery in April, put Liverpool ahead with a 68th-minute free-kick. October 15, 2011, Phil McNulty, “Liverpool 1 - 1 Man Utd”, in BBC Sport
2. The area adjoining this fold or depression.
   He pulled a muscle in his groin.
3. (architecture) The projecting solid angle formed by the meeting of two vaults
4. (euphemistic) The genitals.
   He got kicked in the groin and was writhing in pain.
5. (geometry) The surface formed by two such vaults.

verb

1. To deliver a blow to the genitals of.
   In the scrum he somehow got groined.
   She groined him and ran to the car.
2. (architecture) To build with groins.
3. (literary, transitive) To hollow out; to excavate.
   Down some profound dull tunnel, long since scooped / Through granites which titanic wars had groined. 1918, Wilfred Owen, Strange Meeting

Etymology 2

From Middle English groynen, from a mixture of Old French groignier, grougnier (from Latin grunniō) and Old English grunnian (from Proto-Germanic *grunnōną).

verb

1. To grunt; to growl; to snarl; to murmur.
   Such tunges ſhuld be torne out by the harde rootes, c. 1515–1516, published 1568, John Skelton, Againſt venemous tongues enpoyſoned with ſclaunder and falſe detractions &c.

Etymology 3

noun

1. Alternative spelling of groyne