I don't think cheating is the right word here (ironically), which I think you are kind of acknowledging by putting it in quotes.
Based on your footnote, it sounds like you are more concerned that using a thesaurus is more likely to end with a worse result, since you are likely to use the incorrect word, or to use the word incorrectly.
This sounds more like the opposite of cheating; cheating is about unfairly getting a better result, but this concern is more about accidentally getting a worse result.