perhaps from Α (as a negative particle) and the base of μέρος; properly, to miss the mark (and so not share in the prize), i.e. (figuratively) to err, especially (morally) to sin:--for your faults, offend, sin, trespass.
from περί and πατέω; to tread all around, i.e. walk at large (especially as proof of ability); figuratively, to live, deport oneself, follow (as a companion or votary):--go, be occupied with, walk (about).