| ̷ ̷ ̷ ̷| ̷ ̷ transitive verb
Etymology: under (I) + gird
1. : to gird below : make secure underneath
took measures to undergird the ship — Acts 27:17 (Revised Standard Version)
2. : to brace up : strengthen , support
faith undergirds moral principles — I.G.Whitchurch