The United States Has a Serious Substance Misuse Problem In 2015, over 66 million people aged 12 or older in the United States reported binge drinking and 27.1 million people were current users of illicit drugs or misused prescription drugs. Binge drinking is defined, for men, as having 5 or more standard drinks and, for women, 4 or more standard drinks on the same occasion on at least 1 day ...
I like this answer best because it's brief and to the point. About the only relevant information missing is mention of the finer nuance as to why people ever use illicit rather than illegal. I think it's normally either because the writer wishes to emphasis that the debarring authority is something other than law, or to indicate less than total endorsement of the particular law involved.
The words "illicit" and "elicit" seem to be spelled and pronounced similarly, although their meanings appear different. Is this a coincidence or is there a connection between the two words?
unlawful, illegal, illegitimate, illicit are comparable when they mean contrary to, prohibited by, or not in accordance with law or the law. Otherwise than this negation in character, the words in general carry the same differences in implications and connotations as the affirmative adjectives discriminated at LAWFUL. and this for lawful and legal:
Vice industries might fit. A good example of this usage is an article from Fortune magazine entitled: The 5 Biggest Vice Industries in the World The five industries the article discusses are: Alcohol Tobacco The Military-Industrial Complex Illicit Drugs Gambling