To circumvent is to avoid. Someone who trains elephants but somehow gets out of picking up after them has found a way to circumvent the cleaning of the circus tent.
Circum in Latin means "around" or "round about," and vent- comes from venire, "to come," but painting a picture from these two parts of the word helps. Picture someone circling around a barrier instead of climbing over it. That's what you do when you circumvent. You find a smart way around rules or barriers, or avoid doing something unpleasant altogether.