Gwrthddysg, n. a heresy
Gwrthddywedyd, v. to contradict
Gwrthddywediad, contradiction
Gwrtheb, n. an objection
Gwrthedrych, n. retrospect
Gwrthegni, n. a reaction
Gwrtheiriad, n. antiphrasis
Gwrthenwad, n. antinomasia
Gwrthergyd, n. a repulse
Gwrthern, n. a relation in the eventh degree of affinity