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1. A sudden violent entrance; a bursting in
   "the recent irruption of bad manners"
    
2. A sudden sharp increase in the relative numbers of a population
    
3. A sudden violent spontaneous occurrence (usually of some undesirable condition)
   "the irruption of hostilities"
   - outbreak, eruption

Sounds like: eruption

Derived forms: irruptions

See also: irrupt

Type of: entering, entrance, entry, happening, incoming, ingress, natural event, occurrence, occurrent, population growth

Encyclopedia: Irruption