This is the 757th most frequent Japanese word.
いきなり
Suddenly; abruptly; without warning.
Shows unexpectedness of sudden rain.
いきなり大雨が降ってきた。
It suddenly started pouring rain.
Highlights the abruptness of an emotion.
彼はいきなり怒り出したので驚きました。
I was surprised because he suddenly got angry.
Expresses a sudden transition in conversation.