great deal vs slew

great deal and slew both are nouns.

Word	Noun	Adjective	Verb	Adverb
great deal	Yes	No	No	No
slew	Yes	No	Yes	No

As nouns, great deal and slew are synonyms defined as:

great deal and slew: (often followed by `of') a large number or amount or extent

great deal (noun)	slew (noun)
(often followed by `of') a large number or amount or extent	(often followed by `of') a large number or amount or extent

great deal (verb)	slew (verb)
	turn sharply; change direction abruptly
	move obliquely or sideways, usually in an uncontrolled manner