The Collaborative International Dictionary
Underprop
Underprop \Un`der*prop"\, v. t. To prop from beneath; to put a prop under; to support; to uphold.
Underprop the head that bears the crown.
--Fenton.
Wiktionary
underprop
vb. (context transitive English) To prop from beneath; to put a prop under; to support; to uphold, prop up.