Maria: Do you use this word 'systematic' often in such context or are there other phrases? (I copied the question here because formatting is lost in comments...) I'd say that systematic is often used in that context...to communicate "cunning" or "deliberation" or "evil mastermind" You could say that the country X is systematically destroying the infrastructure of country Y. Humans are systematically destroying animal and wildlife habitat. A very sad but real life example... North American indigenous languages and culture were systematically destroyed by the Catholic church.

Systematic means carefully planned and done step-by-step. You make a system to achieve something. treachery (noun) = evil deception (noun) = to deceive (verb) someone, to lie (verb) to someone So, a systematic course of deception is MORE EVIL because someone thought about it, planned it out and carefully made it happen. This is the idea of premeditation. In law, if a crime is premeditated (planned) then the offense is more serious. If you kill someone in a fight accidentally because you lost your temper, that is bad but if you decide to kill someone ahead of time, that is seen as very cold-blooded. For example, there is movie called "Flowers in the Attic" where a grandmother puts arsenic (a poison) on donuts and feeds them to her grandchildren. Her plan is systematic because EVERY MORNING she puts on the poison and carries it up to them. Step-by-step, she poisons the children...

this would be a step by step plan to lie and cheat to achieve some goal