Ýskra

As defined by the Cleasby & Vigfusson Old Norse to English dictionary:

ýskra

að, = öskra, eiskra, to groan from suppressed anger or fury.

Possible runic inscription in Younger Futhark:ᚢᛋᚴᚱᛅ
Younger Futhark runes were used from 8th to 12th centuries in Scandinavia and their overseas settlements