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
   "The irruption of lemmings occurs cyclically in certain Arctic regions"
    
3. A sudden violent spontaneous occurrence (usually of some undesirable condition)
   "The irruption of violence disrupted the peaceful protest";
   - outbreak, eruption

Sounds like: eruptio

Derived forms: irruptions

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

Encyclopedia: Irruption