hatful vs heap

hatful and heap both are nouns.

Word	Noun	Adjective	Verb	Adverb
hatful	Yes	No	No	No
heap	Yes	No	Yes	No

As nouns, hatful and heap are synonyms defined as:

hatful and heap: (often followed by `of') a large number or amount or extent

hatful (noun)	heap (noun)
as many or as much as a hat will hold	a car that is old and unreliable
(often followed by `of') a large number or amount or extent	a collection of objects laid on top of each other
	(often followed by `of') a large number or amount or extent