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

Even when underlying health conditions are not present, racial disparities persist. —Jallicia Jolly, Forbes.com, 31 May 2026

Depending on the underlying problem, your vet might recommend reducing the dose or suggest an alternative treatment. —The Washington Post, San Diego Union-Tribune, 30 May 2026

Many business leaders like OpenAI CEO Sam Altman argue companies are AI washing, or using the technology as an apt justification for layoffs when in reality, they’re enacted due to another underlying budgetary malady. —Jake Angelo, Fortune, 29 May 2026

Rumbello explains that this dual approach is intended to address the underlying muscular response. —Daniel Fusch, USA Today, 28 May 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