In the Bible, we all know that "removing" or "altering the understanding of that original word" from verses is a sin in Rev. 22:18-19.

San José State University Writing Center www.sjsu.edu/writingcenter, Written by Fatima Hussain
Parentheses and Brackets, Parentheses ( ) are used to enclose additional, non-essential information to clarify, explain, or add a side note in a sentence. Use parentheses to prevent disrupting the flow of a sentence.
Brackets [ ] are used to clarify or explain a part of the sentence that is not present, especially in a direct quotation.

Our addition to this  link from the University of San Jose' 

But using a synonym that has the same "root meaning" can also clarify the verse without altering the baseline of the verse. 

So we use brackets [to clarify] giving the reader a "Heads-Up" that is was not in the original text. This is a "Known" literary tool.