Loose lips sink ships is an American English idiom meaning "beware of unguarded talk".
The phrase originated on propaganda posters during World War II. The phrase was created by the War Advertising Council and used on posters by the United States Office of War Information.
The most famous poster that helped popularize the phrase (pictured at right) was created for the Seagram Distillers Corporation by the designer Seymour R. Goff (also known by the pseudonym "Ess-ar-gee" or Essargee). This type of poster was part of a general campaign of American propaganda during World War II to advise servicemen and other citizens to avoid careless talk concerning secure information that might be of use to the enemy. The British equivalent used "Careless Talk Costs Lives", and variations on the phrase "Keep mum", while in neutral Sweden the State Information Board promoted the wordplay "en svensk tiger" (the Swedish word "tiger" means both "tiger" and "keeping silent"), and Germany used "Schäm Dich, Schwätzer!" (English: "Shame on you, blabbermouth!").
The gist of this particular slogan was that one should avoid speaking of ship movements, as this talk (if directed at or overheard by covert enemy agents) might allow the enemy to intercept and destroy the ships.
There were many similar such slogans, but "Loose lips sink ships" remained in the American idiom for the remainder of the century and into the next, usually as an admonition to avoid careless talk in general.
Some examples of use the phrase outside the World War II propaganda context are:
A pop band, a pop album (by Des Ark), and pop songs by various artists, including Camper Van Beethoven, A Change of Pace, Hit the Lights, and others.
A musical play produced by the American Folklore Theatre.
An episode of the American-animated television program, Fish Hooks.
The title an episode of the American television program Survivor: Heroes vs. Villains, and a variation, "Loose Lips Sink Relationships", is an episode of the American television program Will & Grace.
A repeated lyric in the song "Cherry Tree" by The National.
The title of a paper exploring labiaplasty by Simone Weil Davis of the University of Toronto.
A line in "Deus Ex: Human Revolution" video game at the end of the letter (about evacuation of Federal Emergency Management Agency station MICH.355.sos.7 at Highland Park (Detroit) sent by Joseph Manderley.
A lyric at the beginning of the song Let's Get It Up by AC/DC.
A lyric in the song "Nobody's Safe Chump" by EPMD.
A repeated lyric in the song "XO", from Fall Out Boy's second studio album, From Under the Cork Tree.
A slogan on one of the many shirts of Billy Talent's lead singer, Ben Kowalewicz
A lyric in the song "Covered in Cowardice" by Billy Talent
A mention in the alehouses in the game Tradewinds.
An achievement in a video game called Curve Fever 2.
A lyric at the beginning of the song "Ben Threw" by Of Mice and Men.
A lyric at the beginning of the song "Sweetwater Kill (The Ocean Song)" by the cello rock band Rapustina.
A lyric in Travie McCoy's "Rough Water" ft. Jason Mraz.
A lyric at the beginning of the song "Sexed Up" by Robbie Williams.
A lyric in the song "Beneath the Waves" by Young Guns.
A lyric in the song "Swallow my Pride" by Ramones.
A lyric from the song "I Know Places" by Taylor Swift.
A lyric in the song "Slip of the Lip" by Ratt.
The final line in the song "Seaward" by The Acacia Strain.
A lyric repeated throughout the song "Snitches Get Stitches", from The Amity Affliction's first studio album, Severed Ties.
A lyric in the song "Icebergs" by Madison Bloodbath.
A lyric in the song "I Get Around" by Tupac Shakur.
A lyric in the song "Loose Lips" by Kimya Dawson.
