The Collaborative International Dictionary
Sprack
Sprack \Sprack\ (spr[a^]k), a. [Cf. Icel. spr[ae]kr sprightly, dial. Sw. spr["a]k, spr["a]g, spirited, mettlesome; or Gael. spraic vigor.] Quick; lively; alert. [Prov. Eng. & Scot.]
Wiktionary
sprack
a. (context UK dialectal English) lively, full of energy