to harm - harmful = to cause harm. can be a synonym of to eventually destroy in some contexts. destroy - destructive = to cause so much harm to the thing that it cannot be fixed/repaired (or cured for a living organism) destroy - to be destructive also = to cause so much harm that a thing no longer exists or is demolished. grammatical it is possible to cause so much harm to a person that you eventually destroy them, but in actual daily colloquial use we use "to destroy a person" when discussing or referring to their emotional and/or physiological well being. we use "to cause/causing harm" mostly when discussing or referring to physical injury to a person. Although there is sometimes a little overlap and interchangeability. cancer is a harmful disease to the person, it slowly causes destruction of the persons cancer infected organs and usually eventual death/destruction of the organs, causing death of the person.

being destructive means that you destroy. Harmful means that you hurt, or cause pain. To be destructive, you will probably need to be harmful first. You can bring harm to a wall by hitting it with a hammer. If you hit it too much, you are being destructive (you are breaking parts of the wall) You can also be harmful towards people by treating them badly. If you go too far and cause too much harm, you are being destructive. Hope the helps... happy learning!