- a placebo used in experimental tests of a drug that has noticeable side effects;
"an active placebo mimics the side effects of the experimental drug"
- An active placebo mimics the side effects of the experimental drug.
- The orient has been playing an active role in the world economy.
- He is an active member of the school's stamp club.
- An active volcano may explode at any time.
- Is it wise to engage in active sports at your age?
- She was active as a left-winger in the party.