belly flop vs belly whopper

belly flop and belly whopper both are nouns.

Word	Noun	Adjective	Verb	Adverb
belly flop	Yes	No	No	No
belly whopper	Yes	No	No	No

As nouns, belly flop and belly whopper are synonyms defined as:

belly flop and belly whopper: a dive in which the abdomen bears the main force of impact with the water

Other synonyms of belly flop include belly flopper, belly whop.

belly flop (noun)	belly whopper (noun)
a dive in which the abdomen bears the main force of impact with the water	a dive in which the abdomen bears the main force of impact with the water