Underpinned imp. & p. p. : of Underpin

Example:
BUILDERS, If a flats been Underpinned, how long does it last?

Taxonomy
Webster's New World College Dictionary, yourdictionary, pin, word list, pronunciation, dictionary, online dictionary, thesaurus, websters, synonyms, usage examples, quotes, transitive verb, props, corroborate, substantiate, Wiley Publishing, Publishing, Inc.

Defination from the web:
underpinned from Webster's New World College Dictionary. Meaning of underpinned. Pronunciation of underpinned. Definition of the word underpinned. ... transitive verb underpinned -·pinned′, underpinning -·pin′·ning. to support or strengthen from beneath, as with props ...