Bypass

contournement

(road)

contournement

(circumvention)

dérivation

(alternative passage for a bodily fluid)

déviation

(road)

pontage

(alternative passage for a bodily fluid)

rocade

(road)

contourner

(to avoid an obstacle etc, by constructing or using a bypass)

contourner

(to ignore the usual channels or procedures)

passer outre

(to ignore the usual channels or procedures)