Also found in: Legal.
pit someone or something against someone or something
to set someone or something in opposition to someone or something. The rules of the tournament pit their team against ours. John pitted Mary against Sally in the tennis match.
Set in direct opposition or competition, as in The civil war pitted brother against brother. This idiom alludes to setting fighting cocks or dogs against one another in a pit. [Mid-1700s]
To set someone or something in competition with or opposition to someone or something else: The civil war pitted brother against brother. The match will pit the two greatest boxers against each other. The grading system pits one student against another and discourages cooperation.