Laisser and lasser are two regular French verbs that look and sound almost identical, but they mean completely different things. Laisser means “to let,” “to leave,” or “to allow.” Lasser means “to tire” or “to weary.” The only difference in spelling is a single letter, which is why French learners often confuse them in writing.

The meaning of laisser

Laisser is one of the most common verbs in French. It generally means “to let,” “to leave,” or “to allow something to happen.” It is used constantly in everyday speech.

Some core uses of laisser:

• Laisse-moi tranquille – “Leave me alone.”
• Il a laissé son sac sur la table – “He left his bag on the table.”
• Laisse-moi t’aider – “Let me help you.”
• Elle a laissé la porte ouverte – “She left the door open.”
• Ils m’ont laissé partir tôt – “They let me leave early.”
• Je te laisse le choix – “I’ll let you choose.”

Laisser also appears in the useful construction laisser + infinitive, meaning “to let someone do something” or “to allow something to happen.”

• Laisse-le parler – “Let him speak.”
• Elle a laissé tomber le vase – “She dropped the vase” (literally, “let the vase fall”).

Synonyms and alternatives for laisser

Depending on context, several other verbs can replace laisser:

• Permettre – “to allow, to permit,” for formal permission. Il ne permet pas de fumer ici – “He does not allow smoking here.”
• Autoriser – “to authorize,” for official or formal contexts. La mairie a autorisé l’événement – “The town hall authorized the event.”
• Abandonner – “to abandon, to give up,” when laisser implies leaving something behind for good. Il a abandonné son projet – “He gave up on his project.”
• Quitter – “to leave” a place or a person. Elle a quitté la ville – “She left the city.”

Common expressions with laisser

• Laisser tomber – “to drop, to give up.” J’ai laissé tomber le tennis – “I gave up tennis.”
• Laisser faire – “to let things happen, to not interfere.” Il vaut mieux laisser faire – “It is better to let things be.”
• Laisser tranquille – “to leave alone.” Laisse-les tranquilles – “Leave them alone.”
• Se laisser aller – “to let oneself go.” Elle se laisse aller depuis quelques mois – “She has been letting herself go for a few months.”
• Laisser tomber quelqu’un – “to drop someone, to abandon someone.” Il a laissé tomber ses amis – “He dropped his friends.”

The meaning of lasser

Lasser is far less common than laisser. It means “to tire” or “to wear out,” in the sense of making someone feel bored or exhausted, rather than physically tired. It is most often used in its reflexive form, se lasser, meaning “to grow tired of” or “to get bored of” something.

• Ce discours finit par lasser – “This speech ends up wearing people out.”
• Sa répétition me lasse – “His repetition tires me.”
• Je me lasse de ce travail – “I am growing tired of this job.”
• Elle ne se lasse jamais de voyager – “She never gets tired of traveling.”
• On finit par se lasser de tout – “One eventually grows tired of everything.”
• Il s’est vite lassé du jeu – “He quickly grew bored of the game.”

Synonyms and alternatives for lasser

• Fatiguer – “to tire,” for both physical and mental tiredness. Ce bruit me fatigue – “This noise tires me.”
• Ennuyer – “to bore,” for boredom rather than exhaustion. Ce film m’ennuie – “This film bores me.”
• Épuiser – “to exhaust,” for a stronger degree of tiredness. Cette journée m’a épuisé – “This day exhausted me.”
• Excéder – “to exasperate,” for irritation caused by repetition. Ses plaintes m’excèdent – “His complaints exasperate me.”

Common expressions with lasser

• Sans se lasser – “without growing tired.” Il répète la même chose sans se lasser – “He repeats the same thing without growing tired of it.”
• Lasser la patience de quelqu’un – “to wear out someone’s patience.” Tu finis par lasser ma patience – “You are wearing out my patience.”

How to tell them apart

Both verbs are regular first group verbs, conjugated the same way (je laisse / je lasse, nous laissons / nous lassons, and so on), so conjugation gives no clue. The only reliable way to distinguish them is meaning and the single letter that separates them in spelling.

A simple way to remember the difference: laisser has an extra letter, and it also has a wider, more open meaning, covering “letting,” “leaving,” and “allowing.” Lasser is shorter and narrower, and it always points to tiredness or boredom. If the sentence is about permission or leaving something behind, it is laisser. If the sentence is about growing tired or bored of something, it is lasser.

Pronunciation also differs slightly. Laisser is pronounced with a sound close to the English “lay,” while lasser is pronounced with a shorter “a” sound, closer to the English “lass.” Listening for this difference can help in spoken French, though in fast speech the distinction can be subtle.

Summary

• Laisser means “to let,” “to leave,” or “to allow.” It is a very common, everyday verb, as in laisse-moi tranquille – “leave me alone.”
• Lasser means “to tire” or “to weary.” It is less common and usually appears in its reflexive form se lasser, as in je me lasse de ce travail – “I am growing tired of this job.”
• The spelling differs by a single letter, so meaning and context, rather than conjugation, are the safest guide.
• Synonyms for laisser include permettre, autoriser, abandonner, and quitter.
• Synonyms for lasser include fatiguer, ennuyer, épuiser, and excéder.