This importation from French is pronounced "de-BYOO," "DAY-boo," and "DAY-byoo." As a noun, it means "first public appearance," "beginning of a career," or "formal presentation." Debut is not yet established as a verb in standard usage, although it is appearing ever more frequently in both speech and print: "The actress debuts tonight in a new play." "The company will debut its new model tomorrow." Until debut is accepted as a verb by reliable dictionaries, continue to use the word only as a noun.
Dictionary of problem words and expressions. Harry Shaw. 1975.