Raisonnable vs. sensé
The French words raisonnable and sensé both describe people or actions with sound judgment, but they are used in slightly different contexts. While raisonnable translates closely to "reasonable" and focuses on moderation, rationality, and fairness, sensé translates to "sensible" and emphasizes practical logic, wisdom, and good common sense.
Raisonnable
The word raisonnable describes someone or something guided by reason, fairness, or moderation rather than extreme emotion. It is commonly used to describe level-headed adults, children who are well-behaved, or things that stay within acceptable, moderate limits, such as a fair price or a manageable workload.
Le prix de cette voiture d'occasion est assez raisonnable.
(The price of this used car is quite reasonable.)
Mon neveu a été très raisonnable chez le dentiste ce matin.
(My nephew was very well-behaved at the dentist this morning.)
Il faut rester raisonnable face à cette crise financière.
(We must remain rational in the face of this financial crisis.)
J'ai mangé une quantité raisonnable de gâteau au chocolat.
(I ate a reasonable amount of chocolate cake.)
Ce n'est pas raisonnable de travailler autant d'heures sans faire de pause.
(It is not reasonable to work so many hours without taking a break.)
Sensé
The word sensé describes someone or something that demonstrates good common sense and practical judgment. It is used to indicate that a person, a decision, an idea, or an argument is logical, wise, and makes perfect sense in a given situation.
C'est le conseil le plus sensé que j'aie entendu de toute la journée.
(That is the most sensible advice I have heard all day.)
Vendre la maison maintenant semble être une décision tout à fait sensée.
(Selling the house now seems to be a completely sensible decision.)
Elle est beaucoup trop sensée pour croire à ces rumeurs ridicules.
(She is far too sensible to believe those ridiculous rumors.)
Ton argument est sensé et je vais reconsidérer ma position.
(Your argument makes sense and I will reconsider my position.)
Nous avons besoin d'un plan sensé pour résoudre ce problème technique.
(We need a sensible plan to solve this technical problem.)
Summary
To summarize, use raisonnable when you want to express moderation, fairness, or the absence of excess, such as a fair price, a balanced reaction, or a well-behaved child. On the other hand, use sensé when you want to express that something or someone is highly practical, logical, and full of good common sense, exactly like the English word "sensible".