Let’s start with a list. Thin, slim, lanky, skinny, gaunt, slender. Take a moment and put them in order in your head, from worst to best.
Your list might look something like this: gaunt, skinny, lanky, thin, slim, slender. There might be a few switched words, but it should be about the same. What’s the point? It turns out, that though all these words mean about the same thing in the dictionary, they carry further, emotional, weight.
For example: Brainy means having or showing intelligence.
Bright also means the about the same thing, by the dictionary. Which one sounds better? Which one sounds worse?
Brainy often has negative connotation, and bright has positive connotation.
Same thing for cunning and clever. Cunning sounds sneaky or sly (like a fox!), while clever can mean smart, or quick to understand. They might both have the same dictionary definition, (or a close one) but they have different meanings.
Connotation refers to the additional meanings or definitions beyond the word. There might be emotional weight, attitude, or other implications stressed beyond the dictionary definition.
When writing anything, may it be book, story, or email, it is important to pay attention to word choice. Written words don’t have the tone of voice or attitude behind the meaning, they just are. Paying attention to the connotation can make the reader’s experience more enriching.
Don’t go overboard! The best words are the ones that clearly and concisely state what you want to say. As George Orwell stated, “Let the meaning choose the word.”
Massie, Kristy et al. Grammar the Right Way: Application. Updated ed, Over the Bar Instruction, 2016.