UNDERPIN

[verb] [T] -nn- - to give support, strength or a basic structure to (something)He presented very few facts to underpin his argument.It's a fast-moving film, underpinned by an exciting soundtrack.Gradually the laws that underpinned (= formed part of the basic structure of) apartheid were abolished.Better trade figures are underpinning the dollar (= keeping it at a higher level).When restoring the building, the first priority was to underpin the exterior walls by adding wooden supports along the foundations.