My Answer:
Rhetoric is the art of persuasion, which along with grammar and logic, is one of the three ancient arts of discourse.
Put in your oar: It means to give people one's opinion when they do not want it.
My Explanation:
In simple words, Rhetoric refers to the study and use of written, spoken, and visual language.
In simple words, "Put in your oar": means to give an opinion without being asked.
Done! - ω -