tubful vs tub

tubful and tub both are nouns.

Word	Noun	Adjective	Verb	Adverb
tubful	Yes	No	No	No
tub	Yes	No	No	No

As nouns, tubful and tub are synonyms defined as:

tubful (noun)	tub (noun)
the amount that a tub will hold	a large open vessel for holding or storing liquids
	a relatively large open container that you fill with water and use to wash the body
	the amount that a tub will hold