Con-cert, cyttrefniad; cynganedd: cyttrefnu
Con-cise, byr, cryno; cynnwysfawr
Con-clude, dybenu, gorphen; penderfynu
Con-coct, cydferwi, cymmerwi
Con-cord, cytundeb, cydgordiad, cydsain
Con-course, tyrfa, torf; cyrchfa
Con-crete, cyfuno; casglu
Con-cur, cytuno, cydsynied
Con-demn, collfarnu euogfarnu; anghymmeradwyo
Con-dense, tew, dwys: tewhau