Sounds German. Could be Dutch as well, but then it'd be a rare name and not too common.
Frisch could stand for the province of Friesland, written in old Dutch. 'Frisch' could be derived from 'Frische' and 'knecht' means servant here as well.
Would make sense that that last 'e' would've fallen away somewhere down the generations. Just like writing Vanden Bosch, while Van Den and Van De is very common in front of last names over here.
Getting way off topic here, though. Sorry.