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abrupt; sudden; unexpected
突然の雨に傘を持っていなくて困った。
I was in trouble because I didn't have an umbrella when it suddenly rained.
彼女は突然泣き出して周りを驚かせた。
She suddenly started crying and surprised everyone around.
突然の訪問で相手を困らせてしまった。
My sudden visit caused trouble for them.