From shrewd to gullible

Un lecteur avisé is not a reader who has been advised. Avisé describes somebody whose judgement is good: shrewd, canny, alive to what is going on around him. Un investisseur avisé knows what he is doing, and un choix avisé is a sensible one. The English sense survives in French only inside two fixed pairs, bien avisé and mal avisé, which really do mean well-advised and ill-advised — and even there nobody has given any advice: it is the person’s own judgement being praised or blamed. The noun behind the adjective is the second half of the trap. Un avis is an opinion or a notice — à mon avis, changer d’avis, un avis de passage left in the letterbox, l’avis du comité — and never « advice », which is un conseil. The verb keeps its distance from counselling too: aviser quelqu’un is to notify, in the language of formal letters, while s’aviser de quelque chose is to notice it or to take it into one’s head, as in ne t’avise pas de recommencer.