If possible, it should also be casting a negative light on the person described. For instance:
This assassin is __________ first, and opportunistic second. He primarily seeks to catch his target not only unaware, but in a situation where no one would be able to retaliate after the kill.
The assassin in this case is being described by a person who has nothing positive to say about him, so I would like to be able to fit that theme where appropriate.