groyne vs breakwater

groyne and breakwater both are nouns.

Word	Noun	Adjective	Verb	Adverb
groyne	Yes	No	No	No
breakwater	Yes	No	No	No

As nouns, groyne and breakwater are synonyms defined as:

groyne and breakwater: a protective structure of stone or concrete; extends from shore into the water to prevent a beach from washing away

Other synonyms of groyne include bulwark, groin, jetty, mole, seawall.

groyne (noun)	breakwater (noun)
a protective structure of stone or concrete; extends from shore into the water to prevent a beach from washing away	a protective structure of stone or concrete; extends from shore into the water to prevent a beach from washing away