In French conversation, génial can mean 'great', 'awesome' or 'fanstastic' or anything positive in exactly the same way as 'brilliant' has come to be used in English.

Which is the correct use of the word genial?

The definition of genial is warm, cheerful, good for life or comfort. An example of genial used as an adjective is a genial person which means a very friendly person. An example of genial used as an adjective is genial soil which means soil good for growing plants.

Is genial informal?

Génial is an adjective and is often used in informal conversations to express happiness.