an occasion when someone goes into a place or situation where they are not wanted or expected to be

They complained about excessive government intrusion (= unwanted involvement) into their legitimate activities. 他们抱怨政府过多地侵扰他们的合法活动。

His phone call was a welcome intrusion into an otherwise tedious morning. 他突然来电一点也不令人反感，假若没有这个电话，整个上午会很沉闷。