Origin and usage
The noun watchdog is formed from the verb and noun ‘watch’ and the noun ‘dog’. It was first used in English in the 17th century.
A watchdog was originally a dog that kept watch, and the word’s first recorded use was in Shakespeare’s late play The Tempest. In that text and in later ones it was generally spelled with a hyphen, with the closed form coming into use in the 18th century. Although canine watchdogs still exist, these days they are more likely to be called guard dogs, and that meaning has been superseded by a more recent one. The origins of the first meaning given above were figurative, with people who had some kind of public guarding role being referred to as watch-dogs; it was only in the late 20th century that the term came to be generally used to refer to a person or body with responsibility for ensuring that laws are observed and people are not exploited. In modern society watchdogs abound, and the noun is frequently preceded by another noun (or an adjective) telling you what area the person or organization is operating in: who they investigate or who or what they protect. So there are anti-corruption (or just corruption), antitrust, and anti-graft watchdogs; privacy, ethics and civil liberties watchdogs; consumer and competition watchdogs; nuclear, atomic and telecoms watchdogs. Watchdogs are sometimes described as vigilant and non-partisan, but also as self-appointed and sometimes toothless, showing that the metaphor is still just about alive.
“Hark, hark! Bow, wow, The watch-dogs bark: Bow, wow.”
(William Shakespeare, The Tempest)
“The tyrant now
Trusts not to men: nightly within his chamber
The watch-dog guards his couch, the only friend
He now dare trust.”
(Joanna Baillie, Scottish poet and dramatist)
ombudsman, regulator, czar