underlying

adjective

un·​der·​ly·​ing ˌən-dər-ˈlī-iŋ 

1

a

: lying beneath or below

the underlying rock is shale

b

: basic, fundamental

an investigation of the underlying issues

2

: evident only on close inspection : implicit

3

: anterior and prior in claim

underlying mortgage

4

: of or being present in deep structure

underlying word order

Synonyms of underlying

• basic
• rudimentary
• elementary
• fundamental
• introductory

Examples of underlying in a Sentence

the ocean and the underlying rock

the underlying differences between democracy and dictatorship

Recent Examples on the Web

But the fact that the protests were peaceful is the wrong framing — and the government’s response has done nothing to address underlying problems. — Tiisetso Motsoeneng, semafor.com, 1 July 2026

The risk in each case does not disappear when the underlying story looks calm. — Güney Yıldız, Forbes.com, 1 July 2026

The company first unveiled Mythos to an exclusive group of users earlier this year, before rolling out Fable, a version with the same underlying capabilities but with more guardrails and safety filters, designed for general use. — Tristan Bove, Fortune, 1 July 2026

Beyond just being a nuisance, phorid flies can also be an indicator of more serious underlying issues in your home. — Madeline Buiano, Martha Stewart, 28 June 2026

Word History

First Known Use

1611, in the meaning defined at sense 1a

Rhymes for underlying

• applying
• belying
• complying
• decrying
• defying
• denying
• implying
• outlying
• relying
• replying
• supplying
• undying

Kids Definition

underlying

adjective

un·​der·​ly·​ing ˌən-dər-ˌlī-iŋ 

1

: lying under or below

the underlying rock

2

: fundamental entry 1 sense 1

Medical Definition

underlying

adjective

un·​der·​ly·​ing -ˌlī-iŋ 

: serving as a basis or cause (as of secondary symptoms)

the underlying brain malformation that caused the hydrocephalus

—R. M. Henig