run-in vs spat

run-in and spat both are nouns.

Word	Noun	Adjective	Verb	Adverb
run-in	Yes	No	No	No
spat	Yes	No	Yes	No

As nouns, spat is a hyponym of run-in; that is, spat is a word with a more specific, narrower meaning than run-in:

Other hyponyms of run-in include affray, altercation, fracas, bicker, bickering, fuss, pettifoggery, squabble, tiff, bust-up.

run-in (noun)	spat (noun)
an angry dispute	a young oyster or other bivalve
	a cloth covering (a legging) that covers the instep and ankles
	a quarrel about petty points

run-in (verb)	spat (verb)
	clap one's hands together
	spawn
	engage in a brief and petty quarrel
	clap one's hands or shout after performances to indicate approval
	strike with a sound like that of falling rain
	become permanently attached
	come down like raindrops