How to say "intrusion" in Japanese

Choosing the right word

乱入らんにゅうCommon
noun, suru verb, intransitive verbCovers the sense of bursting or barging into a place, often suddenly and disruptively. It suits contexts like someone forcing their way onto a stage or into a gathering uninvited.
強盗ごうとうが彼かれの家いえに乱入らんにゅうした。↗
The burglar burst into his house.
侵入しんにゅうJLPT N2approx.Common
noun, suru verb, intransitive verbCovers intrusion as an incursion or invasion, entering a territory, building, or other domain from outside. It carries a stronger nuance of trespass or hostile entry than 乱入.
「ピッキングの道具どうぐ無なしで、どうやって侵入しんにゅうした？」「トイレの窓まどがあいた」↗
"With no picks how did you break in?" "The toilet window was open."

Use 乱入 for bursting or barging into a place or event, and 侵入 for entering a territory, building, or system as an incursion or invasion.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

Japanese equivalents

JLPT vocabulary levels are community estimates, not official (no official lists have been published since the 2010 revision).

Say it right, write it right