grit = dirt or sand. A book is gritty if it shows some of the "dirty" side of things. For example, a movie about Hollywood can show just the glamour, or it can show things like actors who cannot find work and have to work as prostitutes. The second movie is gritty. Sophisticated means looking at things in a complicated or intelligent or very cultured way. Someone who thinks McDonalds is the best food ever is not sophisticated. A book that says "Hitler was bad and people who voted for him" is not very sophisticated. A book that explains why people who were very normal, nice persons decided to vote for Hitler, and thought he was the best choice, is more sophisticated.

I think this is a great resource for English learners: https://learnersdictionary.com/ If you are more advanced: https://www.dictionary.com/

A very helpful clarification, but you answered me in the comment, so I can't choose it as a best answer.

Gritty is something raw and real in a sense that it's not altered or censored to make everyone comfortable. It may not be pretty, but it is what it is. It can be rude, it can be dark, and makes no apology for being this way. Sophistication is pretty much the opposite of that. It's something that is polished and classy. It's easy on all the senses. It's clean, it's lovely, and someone or something sophisticated makes a concerted effort to be this way. Two examples of gritty and sophistication personified would be like comparing Amy Winehouse to Audrey Hepburn.

" Not all graphic novels are for kids. Some of the drawings can be gritty and realistic. " Gritty here would mean, ' bold as in discerned suitable for adult consumption '. " It's very smart and sophisticated. " Sophisticated here would mean, ' intricate and subtle '. Thanks : )