Do not use dictionary definitions in papers, unless you’re writing a paper about dictionaries

A word of advice to all students: in almost every subject, no matter what some teacher told you years ago, do not ever waste your time or words repeating a dictionary definition in an academic paper. Whatever Mr. Johnson’s and Mr. Webster’s successors wrote down is descriptive, not authoritative, and almost certainly it is useless for the argument you wish to make. There are obvious exceptions (philology, etymology, etc.), but I have never seen a paper where a dictionary definition serves any purpose other than to motivate my tooth-grinding.