sprack
lively, full of energy
She was apprenticed as a 'pupil teacher,' at fourteen years of age, and deemed to have a more than ordinary chance of doing well and getting on, for she was clever, and what is called 'sprack' in the part of the country where she lived.
Where it comes from
From Middle English sprak, from Old Norse sparkr, sprekr (“lively”) and/or Old Norse sprækr (“lively”), from Proto-Germanic *sparkaz, *sprēkijaz, from Proto-Indo-European *sp(h)er(a)g- (“to strew, sprinkle”). More at spark.
Adapted from the Wiktionary entry sprack (CC BY-SA 4.0).