let¹ / let/ • v. (let·ting; past let) 1. [tr.] not prevent or forbid; allow: my boss let me leave early you mustn't let yourself get so involved. ∎  [tr.] allow to pass in a particular direction: could you let the dog out? a tiny window that let in hardly any light.2. [tr.] used in the imperative to formulate various expressions: ∎  (let us or let's) used as a polite way of making or responding to a suggestion, giving an instruction, or introducing a remark: let's have a drink “Shall we go?” “Yes, let's.” ∎  (let me or let us) used to make a polite offer of help: “Here, let me,” offered Bruce. ∎  used to express one's strong desire for something to happen or be the case: “Dear God,” Jessica prayed, “let him be all right.” ∎  used as a way of expressing defiance or challenge: if he wants to walk out, well, let him! ∎  used to express an assumption upon which a theory or calculation is to be based: let A and B stand for X and Y, respectively.3. [tr.] allow someone to have the use of (a room or property) in return for regular payments; rent: homeowners will be able to let rooms to lodgers without having to pay tax they've let out their apartment.4. [tr.] award (a contract for a particular project) to an applicant: preliminary contracts were let and tunneling work started.PHRASES: let alone used to indicate that something is far less likely, possible, or suitable than something else already mentioned: he was incapable of leading a bowling team, let alone a country.let someone/something alonesee alone.let someone/something be stop disturbing or interfering with: let him be—he knows what he wants.let someone down gently seek to give someone bad news in a way that avoids causing them too much distress or humiliation.let something drop (or fall) casually reveal a piece of information: from the things he let drop, I think there was a woman in his life.let fall Geom. draw (a perpendicular) from an outside point to a line.let fly attack, either physically or verbally: the troops let fly with tear gas.let oneself go1. act in an unrestrained or uninhibited way: you need to unwind and let yourself go.2. become careless or untidy in one's habits or appearance: he's really let himself go since my mother died.let someone/something go1. allow someone or something to escape or go free: they let the hostages go. ∎  dismiss an employee.2. (also let go or let go of) relinquish one's grip on someone or something: Adam let go of the reins| fig. you must let the past go. let someone have it inf. attack someone physically or verbally: I really let him have it for worrying me so much.let in (or out) the clutch engage (or release) the clutch of a vehicle by releasing pressure on (or applying it to) the clutch pedal.let it drop (or rest) say or do no more about a matter or problem.let it go (or pass) choose not to react to an action or remark: the decision worried us, but we let it go.let someone know inform someone: let me know what you think of him.let someone/something loose release someone or something: let the dog loose for a minute. ∎  allow someone freedom of action in a particular place or situation: people are only let loose on the system once they have received sufficient training. ∎  suddenly utter a sound or remark: he let loose a stream of abuse.let me see (or think) used when one is pausing, trying to remember something, or considering one's next words: now let me see, where did I put it?let me tell you used to emphasize a statement: let me tell you, I was very scared!let off steamsee steam.let ripsee rip¹ .let's face it (or let's be honest) inf. used to convey that one must be realistic about an unwelcome fact or situation: let's be honest, your taste in men is famously bad.let slipsee slip¹ .let's pretend a game or set of circumstances in which one behaves as though a fictional or unreal situation were a real one.let's say (or let us say) used as a way of introducing a hypothetical or possible situation: let's say we agreed to go our separate ways.to let chiefly Brit. (of a room or property) available for rent.PHRASAL VERBS: let down (of an aircraft or a pilot) descend before making a landing.let someone down fail to support or help someone as they had hoped or expected. ∎  (let someone/something down) have a detrimental effect on the overall quality or success of someone or something: the whole machine is let down by the tacky keyboard.let something down1. lower something slowly or in stages: they let down a basket on a chain.2. make a garment longer, esp. by lowering the hem. let oneself in for inf. involve oneself in (something likely to be difficult or unpleasant): I didn't know what I was letting myself in for.let someone in on/into allow someone to know or share (something secret or confidential): I'll let you into a secret.let something into set something back into (the surface to which it is fixed), so that it does not project from it: the basin is partly let into the wall.let someone off1. punish someone lightly or not at all for a misdemeanor or offense: he was let off with a warning.2. excuse someone from a task or obligation: he let me off work for the day.let something off cause a gun, firework, or bomb to fire or explode.let on inf. 1. reveal or divulge information to someone: she knows a lot more than she lets on [with clause] I never let on that he made me feel anxious. 2. pretend: [with clause] they all let on that they didn't hear me. let out (of lessons at school, a meeting, or an entertainment) finish, so that those attending are able to leave: his classes let out at noon.let someone out release someone from obligation or suspicion: they've started looking for motives—that lets me out.let something out1. utter a sound or cry: he let out a sigh of happiness.2. make a garment looser or larger, typically by adjusting seams.3. reveal a piece of information: [with clause] she let out that he'd given her a ride home. let up inf. (of something undesirable) become less intense or severe: the rain's letting up—it'll be clear soon. ∎  relax one's efforts: she was so far ahead that she could afford to let up a bit. ∎  (let up on) inf. treat or deal with in a more lenient manner: she didn't let up on Cunningham.let² • n. (in racket sports) a play that is nullified and has to be played again, esp. a when a served ball touches the top of the net.• v. (let·ting; past and past part. let·ted or let) [tr.] archaic hinder: pray you let us not; we fain would greet our mother.PHRASES: let or hindrance formal obstruction or impediment: the passport opened frontiers to the traveler without let or hindrance.play a let (in tennis, squash, etc.) play a point again because the ball or one of the players has been obstructed.