Non-competitive inhibition is like playing soccer with a goalie who can't move from their spot. You're trying to score a goal by kicking the soccer ball into the net, but the goalie is in the way. But this goalie isn't like a normal goalie that you can trick by aiming for a different spot. No matter where you aim, the goalie is always going to be in the way because they can't move from their spot.
In the same way, non-competitive inhibition happens when a molecule (the goalie) gets in the way of an enzyme (the soccer player) and stops it from doing its job. Unlike competitive inhibition, which is like playing against a goalie that you can trick by aiming for a different spot, non-competitive inhibition can't be reversed by changing where the enzyme tries to do its job.
This can happen in our bodies, where certain molecules (the goalies) can bind to enzymes that we need for important chemical reactions. This binding can change the shape of the enzyme, making it unable to do its job properly. As a result, important reactions in the body might slow down or stop completely.