crooner

Crooner is a fairly rare loanword-verb borrowed directly from English, used for singing in the smooth, intimate style associated with mid-century pop crooners (à la Sinatra). It's mostly confined to music journalism and criticism rather than everyday speech.

• Il crooner des ballades dans les clubs de jazz parisiens. — He croons ballads in Parisian jazz clubs.
• Elle a passé la soirée à crooner de vieux standards. — She spent the evening crooning old standards.
• Ce chanteur adore crooner sur des rythmes lents. — This singer loves to croon over slow rhythms.

Crooner as a verb is niche and specific to that smooth, romantic singing style — using it as a generic word for 'to sing' (chanter) overreaches; most French speakers would only ever use the related noun un crooner, not this verb form.