(originally) To fall headlong from a horse. / (Britain, idiomatic) To suffer some accident or misfortune; to fail.

(idiomatic, disapproving) to appear or emerge unexpectedly or inexplicably, frequently in large numbers or quantity.

(idiomatic) To confess; admit the truth. / 1921, B. M. Bower, chapter 6, in Sawtooth Ranch: / 1977 Oct. 23, John Gardner, "The World Of Tolkien," New York Times (retrieved 12 Sept 2013):

(idiomatic) emerging; aspiring; beginning to attract attention or critical acclaim

A surname.

An entertainer who performs in a humorous manner, especially by telling jokes. / (by extension) Any person who is humorous or amusing, either characteristically or on a particular occasion.

Used other than figuratively or idiomatically: see come, across. / (figuratively) To change sides; to cross over to work for the opposition.

(idiomatic, informal, by ellipsis) A polite formula used when one has not heard or understood what has been said, or to indicate surprise.

(historical) An international association of Communist parties, established in 1919 by Vladimir Lenin and dissolved in 1943.

A form of improvisational theatre performed with little predetermination of subject matter and structure, but with interaction with the audience. / An instance of such theatre.