sonreír
/sonreˈiɾ/ · A2 · verb
to smile
😊 son + reír = sub + laugh: a smile is an under-laugh
From Latin subridere: sub (under) + ridere (to laugh). Spanish reír means to laugh, so sonreír is a laugh kept below full volume. English has the same root in ridiculous and deride, and French sourire is built the same way.