hoy vs flatboat

hoy and flatboat both are nouns.

Word	Noun	Adjective	Verb	Adverb
hoy	Yes	No	No	No
flatboat	Yes	No	No	No

As nouns, hoy and flatboat are synonyms defined as:

hoy and flatboat: a flatbottom boat for carrying heavy loads (especially on canals)

Other synonyms of hoy include barge, lighter.

hoy (noun)	flatboat (noun)
a flatbottom boat for carrying heavy loads (especially on canals)	a flatbottom boat for carrying heavy loads (especially on canals)