Þrjózkast

As defined by A Concise Dictionary of Old Icelandic (Geir Zoëga):

þrjózkast

(að), v. refl. to be refractory or rebellious.

Possible runic inscription in Younger Futhark:ᚦᚱᛁᚢᛋᚴᛅᛋᛏ