There are a bunch of those words that sound the same, where one or two letters turns it into something completely different. You'll hopefully be learning stuff you never knew or mastered until the day you die. Maybe you can knock this one off by reading over those definitions a couple times. The 'i' in illicit could also stand for the 'i' in illegal. The 'e' in elicit could stand for the 'e' in evoke. Anyway, hope this helps you or someone else to nail this one down.