the word under has no prefix due to the fact that it doesn't have a root word.
The definition of the prefix sub is: Under or less than.
Para is the prefix best fitting the definition of beside.
The prefix that fits the definition of backward or back is "re-".
the prefix plu means more
Indefinite
The prefix that fits the definition of pseudoscience is "pseudo-", which means false or not genuine.
Its I'am.
good
butts
within
Unconscious
look