/ ˌʌndəˈpɪn; NAmE -dərˈp-/ verb ( -nn- ) [ vn ]
1.
( formal ) to support or form the basis of an argument, a claim, etc. :
The report is underpinned by extensive research.
2.
( technical ) to support a wall by putting metal, concrete, etc. under it
► under·pin·ning noun [ C , U ]