Some homophones, similar-sounding words that don’t mean the same thing, are harmless. But elicit and illicit are not among them. They are completely different parts of speech; choosing the wrong one would be an embarrassing mistake. Moreover, it could mean the difference between asking for a response and instigating dangerous criminal activity.
The word elicit originated in mid-17th century: from Latin elicit- ‘drawn out by trickery or magic’, from the verb elicere, from e- (variant of ex- ) ‘out’ + lacere ‘entice, deceive’. Illicit originated in early 16th century: from French, or from Latin illicitus, from in- ‘not’ + licitus
Elicit as verb:
Illicit as adjective:
Elicit or illicit:
While these two words sound the same when spoken, their meanings are very different. Elicit is a verb, and a synonym of evoke. Illicit is an adjective, and a synonym of illegal. Neither word is ever used as any other part of speech.
Since elicit and evoke both start with the same letter, much the same as illicit and illegal, pairing these words with their synonyms will help you remember which is which, and in what contexts they should be used.
Now that you know the difference between these words, you can be confident that your writing will not suffer from this simple mistake. Any time you have questions about other confusing words, you can check this site for an explanation.