be in a war—
1. (of a nation) be in the state of war (also: be at war):
- We are now in a war to the death with the German Empire.
2. participate in a military campaign:
- They are on the point of putting up a war memorial, though none of the people who were in the war want it.
be in the wars—(Perfect Tense)
1. show signs of rough treatment or injury as a result of fighting, etc.:
- The boy looks as if he has been in the wars.
2. be in bad shape, having had a lot of misfortunes:
- Terry’s been in the wars a bit since his racing career ended—his wife left him and he became an alcoholic.