Definitions for underslungˈʌn dərˈslʌŋ
Random House Webster's College Dictionary
suspended from an upper support, as the chassis of a vehicle from the axles.
more massive at the bottom than the top; squat.
Origin of underslung:
supported from above especially in a vehicle having springs attached to the axle from below
underhung, undershot, underslung(adj)
having a lower part projecting beyond the upper
"an underhung jaw"; "undershot bulldog"
having a low center of gravity; built low to the ground
supported from above (especially from the underside of a wing etc)
having a low center of gravity