Definition of underhill:
(adj) :
(Sussex) (of a road, track or other path) passing along the foot of a hill.
(n) :
A surname.
(n) :
A town in Chittenden County, Vermont, United States.
(n) :
A town in Oconto County, Wisconsin, United States.
(n) :
A neighbourhood of Barnet, borough of Barnet, Greater London, England (OS grid ref TQ2595).
(n) :
A hamlet in East Knoyle parish, Wiltshire, England (OS grid ref ST8730).