con- (means "with")
The prefix for "join" is "re-".
The prefix that can be added to "please" is "dis-" to form "displease".
The prefix that can be added to the word "destructive" is "non-."
Impolite, unpolite
The prefix that can be added to appointment is "re-", forming the word "reappointment."
Rejoin
The prefix that can be added to "imperceptibly" is "un-".
The prefix added to "payment" to make it opposite is "non-."
Pre- is a prefix that can be added to the word monition.
The prefix In- can be added to numerable.
The prefix "non-" must be added to form the word "non-poisonous."
"Re" as in reassign or "un" as in unassigned