General need:
* besoin (pronounced "buh-zwan") - This is the most common and general word for "need". It's used in most situations.
Specific needs:
* avoir besoin de (pronounced "ah-vwar buh-zwan duh") - This means "to need" or "to be in need of". It's used when you are talking about something specific that you need. For example, "J'ai besoin d'eau" means "I need water."
* manquer de (pronounced "mahn-kay duh") - This means "to lack" or "to be lacking". It's used when you are talking about something that you don't have enough of. For example, "Je manque de temps" means "I lack time."
Other words that can be used to express "need" in specific contexts:
* exiger (pronounced "eh-zee-zhay") - This means "to require" or "to demand".
* nécessiter (pronounced "nay-seh-si-tay") - This means "to necessitate" or "to make something necessary".
Examples:
* J'ai besoin d'un stylo. (I need a pen.)
* Il faut que j'aille chez le médecin. J'ai besoin de consulter un médecin. (I need to go to the doctor. I need to consult a doctor.)
* L'enfant manque de nourriture. (The child lacks food.)
Choosing the right word for "need" in French depends on the nuance and context of your sentence.