"Arms" refers to the "arms" or weapons used in wars, and to the embracing "arms" of human beings.
Farewell means Goodbye
So basically writer wants to say goodbye to war.
The story is a combination of WAR & LOVE .
Writer gave stresses on the dual meaning of the word arms. In deserting the Italian army, the protagonist bids farewell to “arms” as weapons. When Catherine dies, he bids farewell to the loving “arms” of his mistress. This interpretation of the title blends the two major themes of the novel:
The answer happens to be passive, I just took the test on edg. and this is correct. I don't understand why you have the wrong answer marked brainliest and approved but please rate 5 stars on this answer so people don't make the mistake.