flatboat vs hoy

flatboat and hoy both are nouns.

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

As nouns, flatboat and hoy are synonyms defined as:

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

Other synonyms of flatboat include barge, lighter.

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