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

The underlying pathology begins years before symptoms become apparent, and once symptomatic disease develops, cognitive problems generally continue to progress. — Lauryn Higgins, Flow Space, 19 Aug. 2026

The operator will get a $400,000 annual base fee, as well as incentive fees equal to 7% of gross revenues, food and beverage sales, and 15% of revenue from sponsorships and premium seating, according to the underlying city legislation. — Miami Herald, 19 Aug. 2026

The new findings provide fascinating insight into how underlying biomechanics work to shape – quite literally – the highly specialized features like tusks seen throughout the animal kingdom. — New Atlas, 18 Aug. 2026

By turning natural language requests into Launcher actions, advanced keyboard and mouse customization becomes easier using the flexibility of the underlying QMK platform. — Mark Sparrow, Forbes.com, 18 Aug. 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