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

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

Expectations that space-based AI will be low cost and profitable underpin SpaceX’s $2.1 trillion valuation.

From Barron's ● Jun. 14, 2026

Co-author Dr. Brodie Popovic said the project provided an opportunity to revisit assumptions that underpin modern cosmology.

From Science Daily ● Jun. 13, 2026

"The increases in spending that underpin this plan will be sustainable and fair," Sir Keir said.

From BBC ● Jun. 11, 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

"It underpins every other conversation we might want to have."

From BBC ● Jul. 11, 2026

Legg also said Microsoft had still not proved its assertion that it has managed to create a theoretical quasi-particle called Majorana, which underpins its approach to quantum computing.

From BBC ● Jun. 24, 2026

In 2013, Jeff Dean was working alongside other artificial-intelligence researchers on speech recognition, using the neural-network technology that underpins today’s large language models.

From The Wall Street Journal ● Jun. 19, 2026

It underpins everything from the bond market, to the stock market, to the mortgage market, to how your local supermarket plans price rises, to how your employer thinks about wages.

From MarketWatch ● Jun. 17, 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

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

From BBC ● Jul. 12, 2026

Our customer service turnaround strategy, underpinned by significant investment, has been transformational.

From BBC ● Jul. 8, 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

Chip designer Nvidia announced a new safety system for humanoids underpinned by its cutting-edge Blackwell chips.

From The Wall Street Journal ● Jul. 4, 2026

They’d often wondered, for instance, why the rating agencies weren’t more critical of bonds underpinned by floating-rate subprime mortgages.

From "The Big Short" by Michael Lewis

Stocks have swung wildly lately with investors assessing, and then reassessing, whether the rally in technology companies underpinning the AI revolution was justified.

From The Wall Street Journal ● Jul. 10, 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

Lam finds the philosophical underpinning of Project Spire troubling.

From BBC ● Jun. 18, 2026

The star business underpinning the estimated $1.8 trillion valuation is Starlink, SpaceX’s space-based broadband product.

From Barron's ● Jun. 7, 2026

That is, to replace its interweaving but independent voices with a more unified, streamlined sound, with the keyboard and cello locked together supportively, underpinning the sparring interplay of the two violins above them.

From "The Story of Music" by Howard Goodall