It's just another trendy word the pundits will adopt readily. As you say, a stopper [if we have to use that term] is a goalkeeper. Yes, the bloke who keeps the goal. Actually, to be honest, goalkeeper is little odd, but there you go.
The pet one that has annoyed me over the last couple of years is that strikers play 'up top'. No they don't. They play 'up front'. They don't play the game on a vertical tactics board, where diagrammatically their name is on top of a group of players in their positions. Strikers play on a horizontal pitch, closest to the opposition goal, at the front of the formation. So no more of this stupid up top please. Up front it should return to being.
I blame Ron Atkinson. In fact, it's probably a safe thing to blame Ron Atkinson for everything. And not just in football either.
we all used to know what players were meant to be like. Wingers were small and nippy, for example. The centre half was meant to be huge and eat children for breakfast. That Bobby Moore guy buggered all that. All golden boy, smoother than a baby's bum and could actually play football. What was he doing in the centre of defence?
