good
eu = good
The prefix that makes "upgrade" mean the opposite is "down-," so "downgrade" means to lower or reduce in quality or status.
The prefix "ben-" means good or well, so the prefix "bene-" in benevolent makes the word mean something that is kind, generous, and showing goodwill towards others.
The prefix "e-" in the word "emit" means "out" or "from." So, "emit" literally means to send out or release something.
The prefix mal means bad or evil.
forward
'Cat' (or 'cata') is a Greek prefix with several possible meanings: down, against, very, bad(ly), or completely. Example: catastrophe (literally "an overturning")
before
separated
the prefix un added to fortunate mean not lucky because fortunate means lucky so adding un makes unfortunate mean not lucky
back
"gymno-" is the greek prefix for "naked". In ancient Greece, men would usually perform athletic exercises or sports while they are naked. That is where we get the word "gymnasium." Literally, a place for naked exercise.