free fall vs decrease

free fall and decrease both are nouns.

Word	Noun	Adjective	Verb	Adverb
free fall	Yes	No	No	No
decrease	Yes	No	Yes	No

As nouns, decrease is a hypernym of free fall; that is, decrease is a word with a broader meaning than free fall:

Other hypernyms of free fall include decrement.

free fall (noun)	decrease (noun)
a sudden sharp decrease in some quantity	the act of decreasing or reducing something
the ideal falling motion of something subject only to a gravitational field	the amount by which something decreases
	a change downward
	a process of becoming smaller or shorter

free fall (verb)	decrease (verb)
	decrease in size, extent, or range
	make become smaller