slip in vs supply

slip in is not a noun while supply is a noun.

Word	Noun	Adjective	Verb	Adverb
slip in	No	No	Yes	No
supply	Yes	No	Yes	No

As verbs, supply is a hypernym of slip in; that is, supply is a word with a broader meaning than slip in:

Other hypernyms of slip in include add, append.

slip in (noun)	supply (noun)
	the activity of supplying or providing something
	offering goods and services for sale
	an amount of something available for use

slip in (verb)	supply (verb)
insert casually	state or say further
	give what is desired or needed, especially support, food or sustenance
	give something useful or necessary to
	circulate or distribute or equip with