Probably from Dutch verstaan (“to understand”); or from Norwegian forstå (“to understand”), itself from Middle Low German vorstân (“to understand”), from Old Saxon farstandan (“to understand”), equivalent to for- + stand. More at forstand.
- (transitive, intransitive, chiefly Scotland) To comprehend; understand.
1714, Joseph Ritson, Scotish song:
- A cripple I'm not, ye forsta me, Tho' lame of a hand that I be; [...]
- forest (attributive)