Clown-ish, trwsgl, gwladaidd
Clum-sy, trwstan, anfedrus, carbwl
Clus-ter, swp, sypyn: ymdyru, ymsypio
Coast-er, orlong; glanforwr
Cob-bler, clytiwr, bongler
Cob-web, gwe'r cor, corwe
Co-erce, attal, rhwystro; cymhell
Cof-fin, arch: gosod mewnarch
Co-gent, grymus; effeithiol
Co-here, cydlynu, glynu; cytuno