intrusion

noun

in·​tru·​sion in-ˈtrü-zhən 

1

: the act of intruding or the state of being intruded

especially : the act of wrongfully entering upon, seizing, or taking possession of the property of another

2

: the forcible entry of molten rock or magma into or between other rock formations

also : the intruded magma

Examples of intrusion in a Sentence

Recent Examples on the Web

Also on Holzherr, humble homesteaders the Knoll family brace for the intrusion of Krem (Matthias Schoenaerts, with more facial piercings than Hellraiser’s Pinhead), leader of a band of interplanetary Brigands. — David Rooney, HollywoodReporter, 24 June 2026

Any other solution, even one motivated by a desire to protect your guests from harm, cannot avoid also looking like an intrusion into personal autonomy and a negative judgment on character. — Judith Martin, Mercury News, 24 June 2026

Overcoming Denied Signals And Electronic Illusions As NATO nations continue to experience GPS interference and drone intrusions, Germany is moving to enhance its defensive capabilities in space. — Zita Ballinger Fletcher, Forbes.com, 23 June 2026

Short for Transparent Secure Memory Encryption, TSME encrypts the entire contents stored in memory, making the data useless to adversaries performing cold boot attacks and similar intrusions requiring physical access. — Dan Goodin, ArsTechnica, 22 June 2026

Word History

Etymology

Middle English, from Anglo-French, from Medieval Latin intrusion-, intrusio, from Latin intrudere

First Known Use

15th century, in the meaning defined at sense 1

Phrases Containing intrusion

• anti-intrusion

Rhymes for intrusion

• allusion
• collusion
• conclusion
• confusion
• contusion
• delusion
• diffusion
• effusion
• exclusion
• extrusion
• illusion
• inclusion

Kids Definition

intrusion

noun

in·​tru·​sion in-ˈtrü-zhən 

1

: the act of intruding : the state of being intruded

2

: the entry by force of melted rock into or between other rock formations

Legal Definition

intrusion

noun

in·​tru·​sion in-ˈtrü-zhən 

1

a

: the entry at common law of a stranger after a particular estate of freehold is determined before the person who holds it in remainder or reversion has taken possession

b

: the act of wrongfully entering upon, seizing, or taking possession of the property of another

2

: a trespassing on or encroachment upon something (as a right)

the Fourth Amendment demands that the showing of justification match the degree of intrusion

—Berger v. New York, 388 U.S. 41 (1968)