Un-sold, anwerthedig, heb ei werthu
Un-sound, afiachus, llygredig
Un-tie, dadglymu, datod
Un-til, hyd at, hyd oni, nes
Un-to, i, at, hyd, hyd at, wrth
Un-wise, annoeth, anghall
Un-yoke, dadieuo, di-ieuo
Up-braid, dannod, edliw
Up-hold, dal i fyny, cynnal
Up-most, uchaf, uchelaf