groyne

Etymology

From Middle English groyn (“snout”), from Old French groign, from Late Latin grunium, grunia, from Latin grunnire (“grunt like a pig”).

noun

1. An often wooden structure that projects from a coastline to prevent erosion, longshore drift etc.; a breakwater.
   Our assimilation into one another had been beautifully timed, with each little revelation of unpleasantness acting as a modest baffler, a groyne to our mutual inundation. Now all of this was going to be flooded, drenched in poisonous ichor. 1993, Will Self, My Idea of Fun