Oker is a alternative form of ocker.
In now _ chiefly _ dialectal terms the difference between ocker and oker
is that
ocker is interest on money; usury; increase while
oker is interest on money; usury; increase.
In transitive now _ chiefly _ dialectal terms the difference between ocker and oker
is that
ocker is to increase (in price); add to while
oker is to increase (in price); add to.
As an adjective ocker
is pertaining to an ocker.