From Longman Dictionary of Contemporary Englishopen season (on somebody)open season (on somebody)CRITICIZEa time when a lot of people criticize someone, or a group of people It seems to be open season on politicians just now. → open season
Examples from the Corpus
open season (on somebody)• There would be an open season on scattered singletons.• Payroll allocations can be changed only during an open season.• In the press, it seems to be open season on overpaid executives.• It is open season for criticising UDCs for lack of planning, lack of strategic thinking and short termism.• That's the West Coast Trail, limited to 8,000 hikers during its open season from mid-April to the end of September.• The grin meant it was open season. 