The war is actually begun! The next gale that sweeps from the north will bring to our ears the clash of resounding arms! Our brethren are already in the field! Why stand we here idle? What is the meaning of the word idle as it is used in this selection? A) inactive B) incomplete C) jealous D) worried

The speaker in this selection is talking about a war having begun, yet he and whomever he is speaking to are doing nothing (not acting), that is to say, they are inactive. Incomplete doesn't make sense here. Jealous doesn't either. Worried makes a bit more sense but not quite. Always insert each of the words in place of the one in question to find the correct answer.