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

Young children, adults over 65, people with weakened immune systems and adults over 50 with underlying conditions can face severe complications and may require hospitalization. —Moná Thomas, PEOPLE, 9 Dec. 2025

The ceasefire does not spell out a path to resolve the underlying basis of the dispute, the longstanding differences over where the border should run. —CBS News, 8 Dec. 2025

The underlying question will be whether the committee will be pressured not to penalize Alabama, knowing it would be seen as penalizing a team for playing an extra game. —Seth Emerson, New York Times, 7 Dec. 2025

According to the Mayo Clinic, frostbite is an injury caused by freezing of the skin and underlying tissues and causes a cold feeling followed by numbness. —Hollie Silverman, MSNBC Newsweek, 7 Dec. 2025

Word History

First Known Use

1611, in the meaning defined at sense 1a

Rhymes for underlying

• amplifying
• beautifying
• certifying
• clarifying
• classifying
• codifying
• crucifying
• edifying
• falsifying
• fortifying
• glorifying
• gratifying

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