Here is a context clues worksheet on the adjective mellifluous. It means “having a smooth rich flow <a mellifluous voice> and “filled with something (as honey) that sweetens.”
It’s not a word used with any real frequency in English. But when you need it–as when it’s time to express one’s feelings about, say, Nina Simone’s voice–well, nothing else will quite do, you know?
If you find typos in this document, I would appreciate a notification. And, as always, if you find this material useful in your practice, I would be grateful to hear what you think of it. I seek your peer review.