present participle of fall about

To laugh so much that one's entire body moves somewhat uncontrollably.

(intransitive, idiomatic) To fall from an upright or standing position to a horizontal or prone position. / (intransitive, idiomatic) Of an argument, to fail to be valid.

(archaic) Epilepsy.

Massive waterfalls located on the Niagara River. / A city in New York near the Falls. / A city in Ontario near the Falls.

(trading) A stock whose price has dropped rapidly.

Alternative spelling of shortfall

Alternative spelling of falloff

Alternative spelling of fallout

Used other than figuratively or idiomatically: see fall, back. / To retreat. / To fail to fulfill a promise or purpose.