(literally, typically with with or against) Fighting in a war.
(figuratively, by extension) (typically with with or against) Vigorously opposed (to); in strong conflict (with).
Synonym: at odds
The decision to separate a child from his parents is at war with our values.
Abbott, 26 In 494 BC, the city was at war with two neighboring tribes. Source: Internet
Acts of heroism coming from women are acceptable, during specific time, like when men are at war, during times of crisis, but they are otherwise often seen as suspicious. Source: Internet
Although it may be anathema to a president disconnected from reality and at war with the truth, the Corporation for Public Broadcasting is vital to the kind of fair and independent news that promotes a well-informed public and strengthens our democracy. Source: Internet
After immense material and human destruction, the conflict ended with a cease-fire in 1953, but the two nations officially remain at war because a peace treaty was never signed. Source: Internet
Although Brunswick was only a small country, Britain was at war with revolutionary France so eager to obtain allies on the European mainland. Source: Internet
Although he had been expected to go into politics and the law, like most of his kinsmen, and although Denmark was still at war with Sweden, his family supported his decision to dedicate himself to the sciences. Source: Internet