ableism is treating one person as lesser, inadequate, or "not as good" based on qualities of any sort
this language has become so pervasive it is incredibly hard to learn your way out of not using
however, it's also some of the most important, imo, because it is so harmful to such a wide range of people
ableist slurs are just words that follow that definition, and here is a non-exhaustive list
-dumb
-stupid
-retarded
-autistic (used as a deprecation)
-lame
-insane
-crazy
and so, so many more
please, please try to stop using them, thanks