bathing tub vs tub

bathing tub and tub both are nouns.

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

As nouns, bathing tub and tub are synonyms defined as:

bathing tub and tub: a relatively large open container that you fill with water and use to wash the body

Other synonyms of bathing tub include bathtub.

bathing tub (noun)	tub (noun)
a relatively large open container that you fill with water and use to wash the body	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