Ystwy, n. a stop, a check
Ystwyad, n. a checking
Ystwyll, n. Epiphany
Ystwyo, v. to check, to restrain
Ystwyr, n. what stretches out
Ystwyrain, v. to be stretching
Ystwyriad, n. a stretching
Ystwyth, a. flexible, pliant
Ystwythder, n. flexibility
Ystwythiad, n. a making pliant