Theological noncognitivism means that the idea of God is just a bunch of confusing words that really don't mean anything at all. It's like when someone tells you a really complicated story that you don't understand, and then you ask them to explain it again but they just use even more confusing words.
Some people believe that the idea of God is like that, and that we can never really know what it means or if it's real. They say that since there's no concrete evidence for God, it's just a made-up idea that people use to explain things they don't understand or to feel better when things are tough.
So, basically, theological noncognitivists think that the concept of God is just a bunch of nonsense that doesn't actually mean anything. It's like a confusing jigsaw puzzle that doesn't have all the pieces, or a riddle that nobody really knows the answer to.