Gwrthymdro, n. self-inversion
Gwrthymdyniad, n. a contending against
Gwrthymddangos, n. counter appearance
Gwrthymddwyn, contrary inference
Gwrthymegnïad, n. a self-exertion against
Gwrthymgyrch, n. counter repetition
Gwrthymladd, n. oppugnancy
Gwrthyni, n. counter energy
Gwrthysgrif, n. a rescript
Gwrwst, n. to cramp