Nouns

(n)groin, inguenthe crease at the junction of the inner part of the thigh with the trunk together with the adjacent region and often including the external genitals
(n)groina curved edge formed by two intersecting vaults
(n)breakwater, groin, groyne, mole1, bulwark, seawall, jettya protective structure of stone or concrete; extends from shore into the water to prevent a beach from washing away

Verbs

(v)groinbuild with groins“The ceiling was groined”