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 blasts took place as police responded to an emergency phone call about an intrusion at a store near the city center, according to Lviv’s regional prosecutor’s office. —Rhea Mogul, CNN Money, 22 Feb. 2026

With these acts in place, Americans can more confidently invest in and make use of AI tools without fear of government intrusion. —Neil Chilson, Fortune, 20 Feb. 2026

Three separate cases for failing to maintain a building in safe working order—involving cases of roof leaks, water intrusion, and drywall damage in individual units—are currently open and under enforcement. —Larry Seward, CBS News, 20 Feb. 2026

Inspectors found widespread water intrusion, corroded piping and deteriorating concrete throughout City Hall and its two-level underground garage. —Dallas Morning News, 20 Feb. 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)