1 to make a piece of equipment work by pressing a switch -- włączać coś
2 to pretend to have a particular feeling, or to behave in a way which is not real or natural for you -- udawać coś
He's not really upset, he's just putting it on.
3 to make music, a film, or some other recording start playing on a machine -- włączać coś , nastawiać coś
Why don't you put on some music?
4 to become fatter and heavier -- przytyć, przybierać na wadze