un·der·gird 
/ˌʌndɚˈgɚd/ verb
un·der·girds; un·der·gird·ed; un·der·gird·ing /ˌʌndɚˈgɚd/ verb [+ obj] chiefly US : to strengthen or support (something) from below — usually used figuratively ▪ Their way of life is undergirded by religious faith.
