erratic, random, prone to err ...1835 rare
from Latin errābundus wandering to and fro, wandering about, from errāre
FIRST DOCUMENTED USE
1835 - see EXAMPLE below
"...while I have listened and looked on like a spectator at a game of blind-man's-buff, or at a blindfold boat-race, have you, with your errabund guesses, veering to all points of the literary compass, amused the many-humoured yet single-minded Pantagruelist, the quotationipotent mottocrat, the entire unit, the single and whole homo, who subscribes himself ..."
From: The Doctor, &c
- Robert Southey