free fall

nouns

the ideal falling motion of something subject only to a gravitational field
free fall
is a type of (narrower)
a free and rapid descent by the force of gravity
"it was a miracle that he survived the drop from that height"
drop, fall
a sudden sharp decrease in some quantity
"a drop of 57 points on the Dow Jones index"; "there was a drop in pressure in the pulmonary artery"; "a dip in prices"; "when that became known the price of their stock went into free fall"
dip, drop, fall, free fall