A singer of popular ballads WordNet 3.0 & Open English WordNet

Crooner is a term used to describe primarily male singers who performed using a smooth style made possible by better microphones which picked up quieter sounds and a wider range of frequencies, allowing the singer to access a more dynamic range and perform in a more intimate manner. Wikipedia

American epithet given primarily to male singers of jazz standards, mostly from the Great American Songbook Wikidata

A singer, particularly a professional singer who performs ballads. Wiktionary

A singer of ballads. Wiktionary (translation)

One who croons; a singer, usually male, especially of popular music. Wiktionary

One who croons. Wiktionary (translation)