Definition

1. Verb:
   • To enter a place suddenly, forcefully, or without invitation: To intrude or burst into a space, often in an abrupt or disruptive manner.
   • To increase in number or intensity very rapidly and suddenly: To undergo a sudden, often explosive, increase in population or activity.
   • To break out or intensify suddenly: To erupt, especially in the context of emotions, conflict, or other volatile situations.

Examples of Usage

• Verb:
  • The protesters irrupted into the government building. (The protesters entered the government building suddenly and forcefully.)
  • The lemming population tends to irrupt every few years. (The lemming population tends to increase very rapidly every few years.)
  • Violence irrupted in the city center after the controversial verdict. (Violence broke out suddenly in the city center after the controversial verdict.)

Advanced Usage

• "to irrupt into": To enter a place or state suddenly and often disruptively.
  • The children irrupted into the room, full of laughter and noise. (The children burst into the room, full of laughter and noise.)
• Used in ecology to describe a sudden, dramatic increase in an animal population.
  • Scientists are studying the factors that cause certain bird species to irrupt southward in some winters. (Scientists are studying the factors that cause certain bird species to suddenly appear in large numbers in southern areas in some winters.)

Variants and Related Words

• Irruption (n): A sudden, violent, or forcible entry; a bursting in. Also, a sudden sharp increase in the relative numbers of a natural population.
  • The irruption of barbarian tribes changed the course of history. (The violent entry/invasion of barbarian tribes changed the course of history.)
  • The irruption of snowy owls was a spectacular sight for birdwatchers. (The sudden appearance of many snowy owls was a spectacular sight for birdwatchers.)

Synonyms

• Intrude: To come or go in without permission or welcome.
• Erupt: To burst forth or break out suddenly and often violently.
• Explode: To increase suddenly and dramatically.
• Burst in: To enter suddenly and forcefully.

Related Phrasal Verbs

• Irrupt into: This is the standard construction for the verb, meaning to enter or break out into a place or state.
  • His anger irrupted into a furious tirade. (His anger suddenly intensified and became a furious tirade.)

Related Idioms

• No specific common idioms center solely on "irrupt," but it is used in formal or descriptive contexts to convey sudden, disruptive entry or increase.

Verb

1. increase rapidly and in an uncontrolled manner
   • The population of India is exploding
   • The island's rodent population irrupted
2. erupt or intensify suddenly
   • Unrest erupted in the country
   • Tempers flared at the meeting
   • The crowd irrupted into a burst of patriotism
3. enter uninvited
   • They intruded on our dinner party
   • She irrupted into our sitting room