"I object it" is wrong, you mean "I object to it." Which is more natural depends on what you actually mean. "I'm against it" is an expression of opinion. You can be against it for practical reasons ("it won't work.") You can be against it for reasons of taste ("it looks ugly.") You can be strongly against something, but you can also be mildly against something. It isn't necessarily emotional. "I object to it" is stronger. It carries the idea that it is against the rules, or against the law, or against ethical principles. Sometimes, it carries the idea that you have been personally insulted or attacked. Here is an example of a mild and friendly situation: "Should we go have ice cream?" "I'm against it, I'm trying to lose weight, but, hey, if everyone else wants to, I'll go along." Here is an example of a serious, insulting attack, and an angry objection: Protesters shouted "Soubry is a Nazi" at conservative MP Anna Soubry. "I object to being called a Nazi," Soubry said.

“I’m against it” sounds more natural. “I object it” is incorrect grammatically, but “I object to it” would work. I hope this helps you. Good luck and good work!

Hi Elena! I assume you want to express dismissal of a specific action, for instance - hitting random people in the face. You may do that (expressing dismissal that is) with the help of the verb "object to" ( please take note of the particle "to"), i.e. "I object to hitting random people in the face". If the object of your sentence is already known from context (hitting random people in the face) you could just replace it with "that", i.e "I object to that". The same goes for being against something.

I'm against it