Background
Behind The Scenes
noun, の adjective
Something that's behind your back is in the background. It's also probably plotting against you, behind the scenes. Sneaky, sneaky.
This is a jukugo word, which usually means on'yomi readings from the kanji. As long as you know the readings for these kanji, you should be able to read this word just fine.
ホラー映画で、背後に何かいるパターンが一番怖い！
In horror movies, the "something's behind you" trope is the most terrifying.
ちょっと！背後から急に話しかけないで、びっくりするから！
Hey! Don't talk to me suddenly from behind, you startled me!
この階段では、レッサーパンダがおそってくることがあるんで、背後に注意してくださいね。
On these stairs, red pandas might attack you. So please be cautious of what's behind you.
背後に敵が潜んでいたことに全く気づかなかった。
I completely didn't notice the enemy lurking in the background.