be at the bottom of somethingbe/lie at the bottom of (something)
to be the real reason for something unpleasant.
I don't know for certain why she dislikes you, but I suspect jealousy is at the bottom of it.
be at the bottom of (something)
To be the fundamental cause of something. Stubbornness is at the bottom of every unresolved disagreement.
be at the bottom of something
If something is at the bottom of a situation, it is the real cause of it. Remember that pride is at the bottom of all great mistakes. Note: You can also say that something lies at the bottom of a situation. This decision quite probably lies at the bottom of the colony's current discontent.
be/lie at the ˈbottom of something
be the basic cause of something: Racist feelings almost certainly lie at the bottom of these recent attacks.