1. : an imaginary argument of no substance advanced in order to be easily confuted or an imaginary adversary advancing such an argument
seems to be looking for a man of straw to belabor — Journal of Forestry
2. : a person usually without means or position who is vested with some nominal or fictitious post or responsibility as a cover in proceedings of doubtful legality or to shield the real author of an action : front , dummy
a man of straw who appears to any summons that may be brought against the paper — F.M.Ford