underside
noun
un·der·side
| \ ˈən-dər-ˌsīd
, ˌən-dər-ˈsīd\
, ˌən-dər-ˈsīd\
Definition of underside
1
: the side or surface lying underneath
2
: a side usually hidden from sight
specifically
: the more unpleasant or reprehensible side
the underside of politics