gobbledegooknoun [ U ]
also gobbledygook uk/ˈɡɒb.əl.di.ɡuːk/us/ˈɡɑː.bəl.di.ɡuːk/informal disapprovinglanguage, especially used in official letters, forms, and statements, that seems difficult or to mean nothing because you do not understand it:
This computer manual is complete gobbledegook.