1) under the weather means not feeling well.
2) It means that a person is currently unemployed — having quit, been fired, or laid off from his or her previous job, or the previous job was temporary and has now ended — and the person has not yet found a new job.
acid chowder, barking at the ants, the big spit, arguing with the worms, etc.
well-seasoned, experienced, elderly, time lasted, antique
C on the 2nd and third sentence
