Raise your hand with the dumb question once. It gets weirdly easier every time after that.

The fear lives entirely in the first time. What you dread is a reaction that almost never comes, and once the room has not laughed, the whole thing loses most of its power. After that it becomes a small ordinary act you can do without much thought, and you spend the rest of your education actually finding things out. Half the class is usually relieved somebody asked.

Pick the class where you are most lost and ask one thing this week, however basic it sounds. Say it plainly rather than dressing it up to sound clever. Notice how many people turn out to have wanted the same answer.