The opposite of judge using a prefix is misjudge.
The opposite of "pronounce" using a prefix would be "mispronounce."
The opposite of noble using a prefix would be ignoble.
The opposite of merciful using a prefix is merciless.
The opposite of active using a prefix is "inactive."
Disobedience
The opposite of "pronounce" using a prefix would be "mispronounce."
The opposite of noble using a prefix would be ignoble.
The opposite of merciful using a prefix is merciless.
The opposite of active using a prefix is "inactive."
unpleasant
The opposite of sever is conjoin.
Anti-social.
Disobedience
The prefix 'dis-' is used in this sense as 'to do the opposite of', as in 'disallow'. To disconnect, therefore, is to act in the directly opposite of 'connect'.
You may be going for the word expatriate.
Construct
The opposite of detach using the prefix ad would be "attach", meaning to connect or fasten something to something else.