1. separate or cause disagreement between two people or things
something drove a wedge between us
A 'wedge' is a piece of wood or metal that is used to separate two objects. You can 'wedge a door open' for example. If something 'drives a wedge between' two people, it is a cause of separation or disagreement. "Their mothers will drove a wedge between the family.", "The parties policy on immigration drove a wedge between the two candidates." This is an idiom used in social and professional contexts.