Actually, pseudo- in itself is a prefix.
It is used at the beginning of a word to mean somewhat or fake depending on the context. Most of the time when you have this prefix in a formal setting, it means something is fake or unreal.
If you are talking about a made up word, the prefix can mean halfway or describe something that is not fully what follows. Some of the best examples of words that have this prefix include the following:
Pseudoscience refers to branches of study that often claim to have scientific backing but actually do not. They masquerade (or pretend) to be associated with real science. Instead, they often do not have scientific research that can justify their claims, or have research that is poorly done and cannot be trusted.
Depending on who you talk to, fields such as paranormal studies (studies of ghosts or the afterlife) can fall into this category.
A pseudonym is a name that someone goes by, but is not their actual name. Most of the time this refers to authors who publish something under a false name, such as Mark Twain, whose real name is Samuel Langhorne Clemens, or Dr. Seuss, whose real name is Theodore Geisel.
These people want to have credit for their work under a different name for a variety of reasons, such as expressing ideas that contradict the public opinion or having stage names that make someone seem more interesting or appealing, like many celebrities.
When someone has cataracts in their eyes, it means that there is thick coating that builds up in their eyes for whatever reason. People who have cataracts are usually older in age and end up getting surgery to remove them so that they can see clearly again.
When this happens, the surgeon needs to replace the part of their eye that they remove with a pseudophakia, which is a false lens that can protect the eye when the natural protection has been removed.
In more informal settings, you can also hear pseudo used as a word in itself. While this is technically not grammatically correct, most people can still understand what you mean.
In this context, it means that the speaker cannot think of another word to describe what they want to say, but the word that they think of does not adequately tell what they mean.