n. A hint about a plan of action that is given out to find out what people will say. John mentioned the class presidency to Bill as a trial balloon to see if Bill might be interested in running. The editorial was a trial balloon to test the public's reaction to a change in the school day.
TRIAL BALLOON
Meaning of TRIAL BALLOON in English
American idioms English vocabulary. Английский словарь американских идиом. 2012