Something that portends war as a cloud portends ram.(noun)
The Century Dictionary (Public Domain)
Use "war-cloud" in a sentence
"The war-cloud grew dark and threatening in April, and on April 17 the"
"The four stopped to look over the sea-wall, to the beach far below, across to the long stone piers forming the artificial sea basin and up to Fort Regent overhanging the town like a war-cloud."
"The leading Covenanters saw in the war-cloud, that which blinded eyes could not see -- the hand of the Lord lifted up against the nation."