sois

Sois is the second-person singular form of the French verb être in the imperative mood. It is also the second-person singular form of être in the present subjunctive, used after que to form clauses expressing doubt, possibility, wish, or necessity (que tu sois).

In everyday use, sois is employed to give informal commands or advice to one person: for example, Sois prudent. Ne sois pas en retard. Its formal or plural counterparts are soyez (you all or you formal) and soyons (let us be). The imperative forms of être are irregular compared with many other French verbs, reflecting the verb’s central role in the language.

As a present subjunctive form, sois appears in subordinate clauses after expressions that require the subjunctive, such as Je veux que tu sois heureux (I want you to be happy) or Il faut que tu sois patient (It is necessary that you be patient). These uses are distinct from the imperative sense, even though the surface form is the same.

Etymologically, sois derives from the verb être, which in turn traces back to Latin esse. In French, the imperative forms often align with the present subjunctive forms, and sois embodies that historical connection as the 2nd person singular of être in both moods.