pay vs pay cash

pay is a noun but pay cash is not a noun.

Word	Noun	Adjective	Verb	Adverb
pay	Yes	No	Yes	No
pay cash	No	No	Yes	No

As verbs, pay cash is a hyponym of pay; that is, pay cash is a word with a more specific, narrower meaning than pay:

pay (noun)	pay cash (noun)
something that remunerates

pay (verb)	pay cash (verb)
dedicate	pay (for something) with cash
bear (a cost or penalty), in recompense for some action
convey, as of a compliment, regards, attention, etc.; bestow
give money, usually in exchange for goods or services
bring in
do or give something to somebody in return
cancel or discharge a debt
make a compensation for
discharge or settle
render
be worth it