[sign up]{v.} 1. To promise to do something by signing your name; join; sign an agreement. •/We will not have the picnic unless more people sign up./ •/John wants to sign up for the contest./ •/Miss Carter has signed up to be the chaperone at the dance./ 2. To write the name of (a person or thing) to be in an activity; also, to persuade (someone) to do something. •/Betty decided to sign up her dog for obedience training./ •/The superintendent has signed up three new teachers for next year./

[signed, sealed, and delivered]{adj. phr.} Finished; completed; in a state of completion. •/"How is the campus renovation plan for the governor’s office coming along?" the dean of the college asked. "Signed, sealed, and delivered," his assistant answered./ Compare: CUT AND DRIED; HOOK, LINE AND SINKER.

[silence gives consent] If you say nothing or do not say no to something, it means that you agree. — A proverb. •/Don’t be afraid to say, if you don’t like something. Silence gives consent./

[silent majority]{n.}, {informal} The large majority of people who, unlike the militants, do not make their political and social views known by marching and demonstrating and who, presumably, can swing an election one way or the other. •/Sidney Miltner is a member of the silent majority./

[silver] See: BORN WITH A SILVER SPOON IN ONE’S MOUTH, EVERY CLOUD HAS A SILVER LINING, HAND SOMETHING TO ONE ON A SILVER PLATTER.

[silver anniversary] or [wedding] {n. phr.} The twenty-fifth wedding anniversary of a couple; the twenty-fifth anniversary of a business or an association, etc. •/"The day after tomorrow is Mom and Dad’s silver anniversary," Sue said to her brother. "I hope you have a nice present picked out."/

[simmer down]{v.}, {informal} To become less angry or excited; become calmer. •/Tom got mad, but soon simmered down./

[Simon Legree]{n.}, {informal} A strict person, especially a boss, who makes others work very hard. •/Don’t talk on the job; the boss is a real Simon Legree./ •/Everybody avoids the foreman. He acts like a Simon Legree./

[simple] See: PURE AND SIMPLE.

[sing a different tune] or [whistle a different tune] also [sing a new tune] {v. phr.}, {informal} To talk or act in the opposite way; contradict something said before. •/Charles said that all smokers should be expelled from the team but he sang a different tune after the coach caught him smoking./ Syn.: CHANGE ONE’S TUNE, DANCE TO ANOTHER TUNE. Compare: LAUGH OUT OF THE OTHER SIDE OF ONE’S MOUTH.

[sing for one’s supper]{v. phr.}, {informal} To have to work for what one desires. •/I realized a long time ago that I had to sing for my supper if I wanted to get ahead in my profession./

[sing in tune] See: IN TUNE.

[single] See: EVERY SINGLE.

[single out]{v. phr.} To select or choose one from among many. •/There were a lot of pretty girls at the high school prom but Don immediately singled out Sally./

[sing one’s praises]{v. phr.} To extol or praise continuously. •/The audience left the concert with everyone singing the praises of the young piano virtuoso./

[sing out of tune] See: OUT OF TUNE.

[sink] See: HEART SINKS.

[sinker] See: HOOK, LINE AND SINKER.

[sink in] or [soak in] {v.}, {informal} To be completely understood; be fully realized or felt. •/Everybody laughed at the joke but Joe; it took a moment for it to sink in before he laughed too./ •/When Frank heard that war had started, it didn’t sink in for a long time until his father was drafted into the army./ Compare: BRING HOME.

[sink one’s teeth into] See: GET ONE’S TEETH INTO.

[sink or swim]{v. phr.} To succeed or fail by your own efforts, without help or interference from anyone else; fail if you don’t work hard to succeed. •/When Joe was fourteen, his parents died, and he was left by himself to sink or swim./ •/Tom’s new job was confusing and no one had time to help him learn, so he had to sink or swim./

[sit] See: GO SIT ON A TACK, ON THE FENCE also FENCE-SITTING.

[sit back]{v.} 1. To be built a distance away; stand away (as from a street). •/Our house sits back from the road./ 2. To relax; rest, often while others are working; take time out. •/Sit back for a minute and think about what you have done./

[sit by]{v.} 1. To stay near; watch and care for. •/The nurse was told to sit by the patient until he woke up./ •/Mother sat by her sick baby all night./ 2. To sit and watch or rest especially while others work. •/Don’t just sit idly by while the other children are all busy./

[sit down]{v.} To sit on a seat or resting place. •/After gym class Jim was tired and was glad to sit down and rest./

[sit in]{v.} 1. To be a member; participate. •/We’re having a conference and we’d like you to sit in./ also [sit in on]: To be a member of; participate in. •/We want you to sit in on the meeting./ 2. To attend but not participate. Often used with "on". •/Our teacher was invited to sit in on the conference./ Compare: LOOK ON.

[sit on]{v.} 1. To be a member of (a jury, board, commission), etc. •/Mr. Brown sat on the jury at the trial./ 2. {informal} To prevent from starting or doing something; squelch. •/The teacher sat on Fred before he could get started with the long story./ •/The teacher sat on Joe as soon as he began showing off./

[sit on a bomb] or [bombshell] {v. phr.}, {informal} To be in possession of anything that is potentially disastrous or dangerous. •/The finance department will be sitting on a bomb unless it finds a way to cut overhead expenses./

[sit on a volcano]{v.}, {informal} 1. To be in a place where trouble may start or danger may come suddenly. •/Bob was in that part of South America before the revolution began. He knew he was sitting on a volcano./ •/The policemen who patrolled the big city slum area that summer were sitting on a volcano./

[sit on one’s hands]{v. phr.}, {informal} To do nothing; fail or refuse to do anything. •/We asked Bill for help with our project, but he sat on his hands./

[sit on the fence] See: ON THE FENCE.

[sit out]{v.} To not take part in. •/The next dance is a polka. Let’s sit it out./ •/Toby had to sit out the last half of the game because his knee hurt./

[sitter] See: ON THE FENCE also FENCE-SITTER.

[sitting on a powder keg] See: SIT ON A VOLCANO.

[sit through]{v.} To watch or listen until (something) is finished. •/The show was so boring that we could hardly sit through the first act./ •/Elaine liked the movie so much that she sat through three showings./

[sit tight]{v. phr.}, {informal} To make no move or change; stay where you are. — Often used as a command. •/Sit tight; I’ll be ready to go in a few minutes./ •/The doctor said to sit tight until he arrived./ •/The gangsters sat tight in the mountains while the police looked for them./ Compare: STAND PAT.

[sitting on top of the world] See: ON TOP OF THE WORLD.

[sitting pretty]{adj.}, {slang} To be in a lucky position. •/The new library is sitting pretty because a wealthy woman gave it $10,000 worth of reference books./ •/Mr. Jones was sitting pretty until his $25,000-a-year job was dropped by the company./