haw-haw vs sunk fence

haw-haw and sunk fence both are nouns.

Word	Noun	Adjective	Verb	Adverb
haw-haw	Yes	No	No	No
sunk fence	Yes	No	No	No

As nouns, haw-haw and sunk fence are synonyms defined as:

haw-haw and sunk fence: a ditch with one side being a retaining wall; used to divide lands without defacing the landscape

Other synonyms of haw-haw include ha-ha.

haw-haw (noun)	sunk fence (noun)
a ditch with one side being a retaining wall; used to divide lands without defacing the landscape	a ditch with one side being a retaining wall; used to divide lands without defacing the landscape
a loud laugh that sounds like a horse neighing