Answer:
People who offer support but not at any personal cost to themselves.
Explanation:
This is the most likely answer to the question. In these lines, Paine tells us that the "summer soldier" and the "sunshine patriot" would most likely shrink from the service of their country. This means that they would most likely not fight when necessary. The words "summer" and "sunshine" imply that these soldiers are only willing to fight as long as conditions are good and they do not have to suffer much.