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

The intrusion of experienced mainstream reporters there figures to be a short-lived. —Dom Amore, Hartford Courant, 19 Apr. 2026

National security officials have long argued that the law is vital for disrupting terrorist plots, foreign espionage, international drug trafficking and cyber intrusions. —Kathryn Watson, CBS News, 17 Apr. 2026

Matt Floca, the performing arts institution’s new president, is leading a series of tours this month that show water damage and intrusion to expansion joints, marble slabs and exterior pavers. —Steven Sloan, Los Angeles Times, 14 Apr. 2026

Matt Floca, the performing arts institution’s new executive director and chief operating officer, is leading a series of tours this month that show water damage and intrusion to expansion joints, marble slabs and exterior pavers. —Steven Sloan, Chicago Tribune, 14 Apr. 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)