A small group of French verbs ending in -oir can also stand alone as masculine nouns, usually preceded by le or l’. This happens because French allows an infinitive to be treated as a thing in its own right, much like English sometimes turns “to know” into “the knowing” in older or more formal writing. In French, this pattern survived and became standard for a handful of verbs, while for most other verbs it never caught on. The result is a set of nouns such as le pouvoir, le savoir, l’avoir, le devoir and le vouloir, each with its own everyday meaning that has drifted somewhat from the plain sense of the verb it came from.

L’avoir

Avoir means “to have.” As a noun, l’avoir refers to what a person or business owns, particularly in a financial sense. In accounting and retail, un avoir is a specific document: a credit note.

• Ses avoirs sont estimés à plusieurs millions – “His assets are estimated at several million.”
• La banque a gelé ses avoirs – “The bank has frozen his assets.”
• Le magasin m’a donné un avoir – “The shop gave me a credit note.”

Synonyms and alternatives:

• les actifs – the standard term in finance and business for “assets,” and more common than avoirs in that context
• les biens – “goods” or “possessions,” the everyday word for what someone owns, and far more common than avoir in general speech
• le patrimoine – “estate” or “wealth,” a more formal word covering property and inheritance

Le devoir

Devoir means “to have to” or “must.” As a noun, le devoir means “duty” or “obligation.” In the plural, les devoirs means “homework,” which is by far its most common everyday use.

• C’est mon devoir de vous prévenir – “It is my duty to warn you.”
• Il a fait son devoir – “He did his duty.”
• As-tu fini tes devoirs? – “Have you finished your homework?”

Synonyms and alternatives:

• l’obligation – “obligation,” a more common and neutral word for a duty imposed by law, morality or circumstance
• la responsabilité – “responsibility,” used when the emphasis is on being accountable rather than on the duty itself
• la tâche – “task,” a plainer word sometimes used instead of devoir for a piece of schoolwork or a chore

Le pouvoir

Pouvoir means “to be able to” or “can.” As a noun, le pouvoir means “power,” in the sense of authority, control or capability. It is also used for political power, as in le pouvoir en place – “the government in office.”

• Le pouvoir corrompt – “Power corrupts.”
• Elle a le pouvoir de décider – “She has the power to decide.”
• Le pouvoir d’achat a baissé cette année – “Purchasing power has fallen this year.”
• Il est arrivé au pouvoir en 2020 – “He came to power in 2020.”

Synonyms and alternatives:

• l’autorité – “authority,” used when the focus is on the right to command rather than on capability
• la capacité – “capacity” or “ability,” used for what someone is able to do rather than the control they hold
• la puissance – “might” or “strength,” often preferred over pouvoir in political, military or physical contexts, and arguably more common in those settings

Le savoir

Savoir means “to know” a fact or “to know how” to do something. As a noun, le savoir means “knowledge,” usually in a fairly formal or academic sense.

• Le savoir est une richesse – “Knowledge is a form of wealth.”
• Il partage son savoir avec ses étudiants – “He shares his knowledge with his students.”
• Le savoir scientifique évolue sans cesse – “Scientific knowledge is constantly evolving.”

Synonyms and alternatives:

• la connaissance (or plural les connaissances) – “knowledge,” by far the more common word in everyday French; savoir tends to sound more literary or formal by comparison
• la culture – used for general or well-rounded knowledge, as in la culture générale, “general knowledge”
• l’érudition – “scholarship” or “learning,” a more formal word for deep, wide-ranging knowledge

Compounds built on savoir

Savoir also appears as the first part of several fixed compound nouns, each written with hyphens and each describing a practical skill rather than pure knowledge.

• le savoir-faire – “know-how.” Literal translation: “knowing how to do.” Figurative translation: practical skill or expertise in getting something done.
• le savoir-vivre – “good manners.” Literal translation: “knowing how to live.” Figurative translation: knowledge of proper social behaviour and etiquette.
• le savoir-être – “interpersonal skills.” Literal translation: “knowing how to be.” Figurative translation: the ability to conduct oneself appropriately around other people.

Le vouloir

Vouloir means “to want.” As a noun, le vouloir means “will” or “volition,” but it is rare outside literary, philosophical or set expressions. The most common survivor is the phrase le bon vouloir.

• Je le ferai selon votre bon vouloir – “I will do it as you see fit.” Literal translation: “according to your good will.” Figurative translation: at your discretion, whenever and however you decide.
• Le vouloir et le pouvoir sont deux choses différentes – “Willing and being able are two different things.”

Synonyms and alternatives:

• la volonté – “will” or “willpower,” the standard everyday word; vouloir as a noun is much rarer and sounds noticeably more literary by comparison
• le désir – “desire,” used for a wish or longing rather than an act of will
• l’envie – “urge” or “wish,” a common, casual word for wanting something

Summary

Avoir, devoir, pouvoir, savoir and vouloir are the main French -oir verbs that double as nouns, each denoting a fairly abstract idea tied loosely to its verb: possession, obligation, authority, knowledge and will. Devoir and pouvoir are everyday words, avoir is mostly confined to financial contexts, while savoir and especially vouloir lean literary and are often replaced in ordinary speech by connaissance and volonté. Savoir also survives strongly in the compound nouns savoir-faire, savoir-vivre and savoir-être.