(transitive) To support from below with props or masonry. / (transitive, figuratively) To give support to; to corroborate.

simple past tense and past participle of underpin

present participle of underpin

A support or foundation, especially as a structure of masonry that supports a wall. / (figuratively) A basis for something. / (figuratively, humorous) The lower body or legs.

Third-person singular simple present indicative form of underpin

plural of underpinning

One who, or that which, underpins.

plural of underpinner