The crossword solution for the term 'Smooth Operator Songstress' is SADE, a four-letter word. Sade is a Nigerian-born British singer, songwriter, and record producer who rose to fame in the 1980s with her debut album Diamond Life. She is best known for her hit single 'Smooth Operator' which was released in 1984 and has since become an iconic classic. Her music is a mix of soul, jazz, funk, and soft rock. She has sold over 75 million records worldwide and has won numerous awards, including two Grammy Awards.