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.
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.