An intrusion is a deliberate move into someone else's territory — either literal or figurative. When your sister interrupts your conversation with that girl from math class, that's an intrusion. If someone breaks into your home, that's also an intrusion.

First used in the late 14th century, the noun intrusion derives from the Latin word intrudere, which combines the prefix in-, meaning "in," and trudere, meaning "to thrust, push." If someone reads your diary, that's considered an intrusion of privacy. Ordering a Muslim woman to take off her veil would be considered an intrusion on religious beliefs. You may remember intrusion used in science class to describe molten rock that forms in an earlier rock formation.

Definitions of intrusion
  1. noun
    entrance by force or without permission or welcome
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    type of:
    entering, entrance, entry, incoming, ingress
    the act of entering
  2. noun
    entry to another's property without right or permission
    synonyms: encroachment, trespass, usurpation, violation
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    an encroachment or intrusion
    type of:
    actus reus, misconduct, wrongdoing, wrongful conduct
    activity that transgresses moral or civil law
  3. noun
    any entry into an area not previously occupied
    synonyms: encroachment, invasion
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    type of:
    entering, entrance
    a movement into or inward
  4. noun
    the forcing of molten rock into fissures or between strata of an earlier rock formation
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    type of:
    geologic process, geological process
    (geology) a natural process whereby geological features are modified
  5. noun
    rock produced by an intrusive process
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    type of:
    rock, stone
    a lump or mass of hard consolidated mineral matter
Word Family

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