(Cockney rhyming slang) A hat.

(idiomatic) Equivalent retribution; an act of returning exactly what one gets; an eye for an eye.

A not-for-profit company or organization.

(Of a company or organization) providing goods or services but not for the purpose of making a profit.

Initialism of field Of research. / Initialism of frame of reference.

Initialism of Fellowship of Reconciliation, any of a number of religious nonviolent organizations, particularly in English-speaking countries.

(sports) A game or time period in which a player did not manage to sustain a particular attainment. / (baseball) An instance in which a player did not get a hit in a game.

(idiomatic) One who persists in an effort in spite of harmful or unpleasant results.

(obsolete, idiomatic) To beg out of a prison window with a cap, or box, let down at the end of a long string.

To wager everything. / (idiomatic) To try everything possible or do every last thing possible in a final attempt.