Posted on 23rd April 2021 by melyn Effeythus is the Cornish word for effective Yes, effective in Cornish is effeythus Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Post navigationPrevious post: Hwetegves is the Cornish word for sixteenthNext post: Horsen is the Cornish word for son-of-a-bitch