(transitive) To be treacherous or faithless to; betray. / (transitive) To fail to keep; to renege on. / Used other than figuratively or idiomatically: see go back, on.

(navigation) A bearing taken pointing to the exact opposite direction to the direction heading

(idiomatic, intransitive) To act with reserve; to contain one's full measure or power. / (idiomatic, transitive) To contain; stop.

(intransitive) To maintain distance. / (intransitive) To abstain from participation.

(uncountable, linguistics) The process by which a new word is formed from an older word by interpreting the former as a derivative of the latter, often by removing a morpheme (real or perceived) from the older word, such as the verb burgle, formed by removing -ar (perceived as an agent-noun suffix) from burglar.

A small, controlled fire set in the path of a larger uncontrolled fire, in order to limit the spread of the large fire by removing its fuel.

(idiomatic) To recover from a negative without seemingly any damage. / (of a message, usually an email) To be returned to the sender because it is undeliverable.

A slap delivered with the back of one's hand instead of the palm-side of an open hand. / (martial arts) A controlled landing, slapping to the mat with one's back.

(transitive) To return something to its original place. / (intransitive, nautical) To turn back; to return. / (transitive) To postpone an arranged event or appointment.

(intransitive) To return to a place. / (intransitive) To return to one's possession, especially of memories.