réagi

Réagi is the past participle of the French verb réagir, which means to react. It is used with the auxiliary avoir to form perfect tenses, as in j'ai réagi, tu as réagi, il a réagi, nous avons réagi, vous avez réagi, ils ont réagi. The verb réagir comes from re- plus agir, conveying a sense of acting again or in response to a stimulus.

As a past participle, réagi is typically invariable when there is no preceding direct object. When a direct object precedes the participle, the past participle may agree in gender and number, yielding forms such as réagie (feminine singular), réagis (masculine plural) or réagies (feminine plural). For example: Les émotions qu'il a réagies étaient vives.

In ordinary usage, the form réagi appears most often in the masculine singular in standard perfect tenses. The agreement forms occur in more careful or specific constructions where the preceding object demands it, such as in relative clauses or with certain emphases.

See also: réagir, réaction, the concept of reaction in psychology and philosophy, and the general formation of past participles with the auxiliary avoir in French.