piles vs slews

piles and slews both are nouns.

Word	Noun	Adjective	Verb	Adverb
piles	Yes	No	No	No
slews	Yes	No	No	No

As nouns, piles and slews are synonyms defined as:

Other synonyms of piles include dozens, gobs, heaps, lashings, loads, lots, oodles, rafts, scads, scores, stacks, tons, wads.

piles (noun)	slews (noun)
a large number or amount	a large number or amount
venous swelling external or internal to the anal sphincter