Reason for some hisses

• One way of letting down tail end of pants
• The act of letting the air out of something
• A contraction of economic activity resulting in a decline of prices

Douglas Harper's Etymology Dictionary Word definitions in Douglas Harper's Etymology Dictionary
1891, "release of air," from deflate + -ion . In reference to currency or economic situations, from 1920.

Wiktionary Word definitions in Wiktionary
n. 1 An act or instance of deflate. 2 (context economics English) A decrease in the general price level, that is, in the nominal cost of goods and services as well as wages. 3 (context economics euphemistic English) An economic contraction.

Wikipedia Word definitions in Wikipedia
Deflation is a 2001 micro-budget short film, written and directed by Roger Ashton-Griffiths . It stars Del Synnott , features Keira Knightley , who also worked as part of the crew, and Sharman Macdonald , her mother, who co-edited the film.

Longman Dictionary of Contemporary English Word definitions in Longman Dictionary of Contemporary English
noun COLLOCATIONS FROM CORPUS ■ NOUN price ▪ In the original neoclassical synthesis the practical relevance of a process of price deflation for establishing full employment was regarded as minimal. ▪ Fierce price deflation , increased competition and rising ...