突発

1. Origins, structure, and basic meaning

• Structure: 突発, read とっぱつ, denotes something arising suddenly without warning or prior planning.
• Basic usage: The noun names a sudden occurrence, while 突発的な modifies an event or request as unforeseen and unplanned.

2. Common pitfalls and similar expressions

• Noun 突発 and modifier 突発的な
  • 突発 names a sudden occurrence, while 突発的な modifies an event or request as arising outside prior plans. The key point is lack of warning or planning, not merely rapid timing.