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

However, economists cautioned that the solid-looking topline employment numbers mask underlying weakness in the labor market. —Alicia Wallace, CNN Money, 8 May 2026

Critically, agents can alter their own code (though not the underlying LLM), and get better at doing so. —Matthew Hutson, IEEE Spectrum, 7 May 2026

And this underlying material of Doc Martin really connected to me and my family were fans of the show. —Abby Stern, HollywoodReporter, 6 May 2026

The reality is that Kenya, like many other African countries, isn’t capable of taking full advantage of economic opportunities presented by the boom in AI and data centers due to the inadequacy of basic underlying infrastructure. —Martin K.n Siele, semafor.com, 6 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
• stupefying
• supplying

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