(idiomatic, Southern US) To engage in idle conversational fantasies.

A high-pitched whistle, inaudible to humans, used to train dogs. / (figuratively) That which is understood only by a narrow demographic.

(idiomatic) Extremely brief and hurried.

(politics, intransitive) To make a brief stop on a campaign tour to make a speech or perform some other type of public electioneering.

(idiomatic) A small train station. / (politics) A brief stop on a campaign tour to make a speech or perform some other type of public electioneering.

A tin whistle.

The action of a whistleblower.

To whistle in appreciation or sexual interest.

(sports) The blow of the whistle by the referee or other adjudicator signifying the end of the match.

A whistle, of two notes, to signify sexual interest in someone.