n.
Pronunciation: ' ə n-d ə r- ˌ pi-ni ŋ
Function: noun
Date: 15th century
1 : the material and construction (as a foundation) used for support of a structure
2 : something that serves as a foundation : BASIS , SUPPORT ― often used in plural <the philosophical underpinning s of educational methods>
3 : UNDERWEAR ― usually used in plural
4 : a person's legs ― usually used in plural