A noun appearing as N. chwîn “giddiness, faintness” in The Etymologies of the 1930s under the root ᴹ√SWIN “whirl, eddy” (Ety/SWIN), where initial sw became chw as usual for Noldorin of the 1930s.

Neo-Sindarin: This word is often adapted as ᴺS. hwîn for purposes of Neo-Sindarin, as suggested in Hiswelókë’s Sindarin Dictionary (HSD), since initial initial sw became voiceless w in Sindarin of the 1950s and 60s. I prefer the spelling ᴺS. whîn as more consistent with Tolkien’s orthography in the 1950s and 60s.