The correct spelling of the word "most smoothing" is /moʊst ˈsmuːðɪŋ/. The first part, "most," is pronounced as /moʊst/, with a long "o" sound like in "boat" and a soft "st" sound at the end. The second part, "smoothing," is pronounced as /ˈsmuːðɪŋ/, with a long "oo" sound as in "smooth" and a hard "th" sound at the end. This word is often used to describe a product or activity that has a calming or relaxing effect on the mind and body.
The word "most smoothing" does not have a specific etymology as it is not a recognized word or phrase. However, if you are referring to the word "smoothing" alone, the etymology of it can help. "Smoothing" is a verb form of the adjective "smooth" which comes from the Old English word "smōth" meaning "level, even, free from roughness". It has Germanic origins and is related to the Old High German word "smuot" and Old Norse word "smjūga". Over time, the word "smooth" has been used to describe objects or surfaces that are not rough or uneven, and it can also be metaphorically used to suggest a sense of ease or comfort.