Étonnant vs. surprenant

'Étonnant' and 'surprenant' are two French adjectives commonly used to express the idea of surprise or amazement. While closely related and often interchangeable, they can carry slightly different connotations and usage contexts.

Étonnant

Indicates something that is astonishing or amazing, often implying it is unexpected or extraordinary in some way.
C'est étonnant de voir à quel point la ville a changé en dix ans.
(It's astonishing to see how much the city has changed in ten years.)
Il a réussi cet exploit ; c'est vraiment étonnant !
(He managed that feat; it's truly amazing!)
La rapidité de sa guérison est étonnante.
(The speed of his recovery is astonishing.)

Surprenant

Describes something that causes surprise because it is unexpected or unusual. The term can imply a subtler level of astonishment compared to 'étonnant'.
Il a pris une décision surprenante qui a changé le cours des évènements.
(He made a surprising decision that changed the course of events.)
C'est surprenant de te trouver ici à cette heure-ci !
(It's surprising to find you here at this time!)
Le résultat du match était vraiment surprenant.
(The result of the match was really surprising.)

Summary

While both 'étonnant' and 'surprenant' relate to the concept of surprise, 'étonnant' implies a sense of amazement or wonder, often associated with something remarkable, whereas 'surprenant' emphasizes the unexpected nature of an event, situation, or characteristic without necessarily invoking marvel. The choice between these words depends on the degree and type of surprise being expressed.