underpin

American  

[uhn-der-pin] / ˌʌn dərˈpɪn /

verb (used with object)

underpins, present (3rd person singular) underpinned, past participle, past underpinning present participle

1. to prop up or support from below; strengthen, as by reinforcing a foundation.

2. to replace or strengthen the foundation of (a building or the like).

3. to furnish a foundation for; corroborate.

   The author's conclusions are underpinned by references to experimental findings.

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underpin British  

/ ˌʌndəˈpɪn /

verb

1. to support from beneath, esp by a prop, while avoiding damaging or weakening the superstructure

   to underpin a wall

2. to give corroboration, strength, or support to

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Other Word Forms

Inflected Forms

Participles

• underpinning
  present
• underpinned
  past

Conjugated Forms

Present

• underpin
  simple
• underpins
  simple
• have underpinned
  perfect
• has underpinned
  perfect
• am underpinning
  progressive
• are underpinning
  progressive
• is underpinning
  progressive
• have been underpinning
  perfect progressive
• has been underpinning
  perfect progressive

Past

• underpinned
  simple
• had underpinned
  perfect
• was underpinning
  progressive
• were underpinning
  progressive
• had been underpinning
  perfect progressive

Future

• will underpin
  simple
• will have underpinned
  perfect
• will be underpinning
  progressive
• will have been underpinning
  perfect progressive

Etymology

Origin of underpin

First recorded in 1515–25; under- + pin

Explanation

To underpin is to justify or support the ideas behind something, the way your extensive research underpins your self-published book on ice cream trucks in the United States. Whenever you substantiate someone's claims, theories, or stories, you underpin them. A slightly different way to underpin is to form the basis or foundation of something: "A philosophy of empathy and kindness underpins all the interactions at my wonderful summer camp." This verb can also be used in a more literal way, to mean "support from below," the way the foundation of a house underpins everything that's built on top of it.

Example Sentences

See Examples For:

underpin underpins underpinned underpinning

Asian currencies were mixed against the dollar in early trade, but may strengthen amid signs of a pause in the U.S.-Iran conflict that could underpin appetite for risky assets.

From The Wall Street Journal ● Jul. 26, 2026

AI models that underpin tools like chatbots and image generators are known as agents when they act autonomously to carry out tasks in the real world.

From Barron's ● Jul. 22, 2026

Some of that will be spent on the robotaxis and humanoid robots that underpin Tesla’s valuation, although progress has been slower than expected.

From MarketWatch ● Jul. 21, 2026

The combined entity would provide “diversity of revenue streams,” with advertising and subscription fees, “providing a resilient and durable business model which will underpin its long-term success,” the companies said.

From Los Angeles Times ● Jul. 6, 2026

The AIG FP traders present were shocked by how little thought or analysis seemed to underpin the subprime mortgage machine: It was simply a bet that home prices would never fall.

From "The Big Short" by Michael Lewis

What underpins this is a determination to tear up two formulas that have long formed the backbone of how UK governments allocate money.

From BBC ● Jul. 17, 2026

The element of chance, and random interaction, that underpins “Strangers on a Train” has a peculiar resonance in today’s internet age, when social networks can bring together individuals who never actually meet.

From The Wall Street Journal ● Jul. 10, 2026

Large language models are the technology that underpins chatbots and many other AI tools, with their capacity to crunch through colossal amounts of digital data.

From Barron's ● Jul. 8, 2026

Much of that cash is expected to be used for SpaceX’s long-term efforts on pricey projects ranging from space-based data centers to developing Starship, a massive rocket that underpins much of the company’s plans.

From MarketWatch ● Jun. 22, 2026

It is quiet, and when the belling tower strikes the late hour, it doesn’t break the silence so much as it underpins it.

From "The Name of the Wind" by Patrick Rothfuss

The result was underpinned by stronger prices for its core commodities, including iron ore, copper, aluminum and lithium.

From The Wall Street Journal ● Jul. 29, 2026

These fixed roles are underpinned by a number of key principles, some of which are:

From BBC ● Jul. 12, 2026

The company’s loan portfolio is expected to grow 7% in 2026, underpinned by government stimulus measures and an improving economic outlook, the analysts estimate.

From The Wall Street Journal ● Jul. 7, 2026

Energy-sector earnings will be affected in coming months, but the stock market more broadly will be underpinned by the forecast for “robust double digit earnings growth,” he adds.

From MarketWatch ● Jul. 6, 2026

The frilled skirt was underpinned with buckram to make it flare.

From "The God of Small Things" by Arundhati Roy

So if you accept the data underpinning momentum investing, and you are willing to take the long view, now is an excellent time to take a closer look.

From MarketWatch ● Jul. 22, 2026

The one thing underpinning the North Africans' success has been long-term investment backed by the country's King Mohammed VI.

From BBC ● Jul. 4, 2026

Despite the concerns, resilient supplies and strong harvest progress are underpinning confident market sentiment, the FAO said.

From The Wall Street Journal ● Jul. 3, 2026

Even the most altruistic acts have some psychological or emotional underpinning.

From MarketWatch ● Jun. 3, 2026

But in the Andean past, the long, puffy bolls of South American cotton, some varieties naturally tinted pink, blue, or yellow, were the soft underpinning of Andean culture.

From "1491" by Charles C. Mann