Captain America has been the alter ego of Steve Rogers, a frail young man who was enhanced to the peak of human perfection by an experimental serum, in order to aid the United States government’s efforts to win World War II. Captain America wears a costume that bears an American flag motif, and is armed with a nearly indestructible shield that can be used for defense and can also be thrown as a weapon.
A World War II veteran who was enhanced to the peak of human physicality by an experimental serum, frozen in suspended animation, and is now struggling to adjust to the modern world. Thanks again, wikipedia!