The words elicit and illicit aren't exactly homophones (for most people anyway), but the words sound similar enough that they're confused frequently. One is a verb that means to bring out, while the other is an adjective that indicates something forbidden.
So let's look at the differences between elicit and illicit and when to use each.
Elicit vs. Illicit
Elicit is a verb that indicates something was drawn forth or from someone or something. For instance, a person may elicit a response by asking a question of another person.
Illicit, on the other hand, is an adjective that is synonymous with unlawful. For instance, running red lights is an illicit act.
Here are a few examples of elicit and illicit:
Correct: The owners hoped the coupon would elicit new business.
Incorrect: The owners hoped the coupon would illicit new business.
Correct: Theft and forgery are only a couple of his many illicit activities.
Incorrect: Theft and forgery are only a couple of his many elicit activities.
Of course, it is possible for someone to use bribery or blackmail to elicit illicit activities out of another person, but these two words are usually traveling in separate sentences.
No matter what type of writing you do, mastering the fundamentals of grammar and mechanics is an important first step to having a successful writing career.