Fist-pumping is the move where you bend your arm and punch the air with a closed hand, held in front of your body, because you are very pleased or thinking “come on, we can do this.” Sports fans do it when a goal goes in; someone might do a small one after good news. It can name the move itself, or describe a person or a song that feels full of that fired-up energy — a fist-pumping chorus. Though actually, used of a person it can be a little teasing, as if they are trying a bit hard to look excited. It is not a punch at anyone; the air is the only thing you hit.