fair game

(a) fair game (for sth) (someone who is considered permissible to attack or abuse in some way because they have left themselves weak or exposed) — легкая добыча; постоянная мишень; объект постоянных нападок, травли и т. п.; {букв.: дичь, на которую разрешено охотиться}

Example 1: Journalists always regard movie stars as fair game. (McGraw-Hill Dictionary of American Idioms and Phrasal Verbs)

Example 2: After she (had) admitted offering money in return for votes she became fair game among the reporters in Fleet Street.

Example 3: I don't like seeing articles exposing people's private lives, but politicians are fair game for that kind of criticism. (McGraw-Hill Dictionary of American Idioms and Phrasal Verbs)

Example 4: It's what the Army's all about. So if in any way you're different, if you're black or if you're short or if in any way you're different, you're fair game for the bullies.

Example 5: "Come in," Rosemary promptly invited, and opined, "You look worse than I feel. What's wrong?" "I've been given the sack," Leith told her shakily, and, over coffee, gave her a blow-by-blow account. In Rosemary's book, "lecherous, cretinous, oversexed reptile" was too polite a term for a man who seemed to think any female working for his father was fair game. "You should have hit him," she said, equally outraged on Leith's behalf. "I might have done if I could have got my arms free," Leith replied, and took another sip of her coffee. (Jessica Steele, "His woman" )

Example 6: The boys at school who had to have their heads shaved because of nits were always fair game for the rest of the school. They suffered the kind of cruel teasing that drew them together, regardless of past differences, into closely knit little groups sharing a common stigma. Frankie could imagine only one thing worse than being counted amongst the "baldies". He had always dreaded being singled out as the only boy in the school with nits, a solitary outcast with a shaved head. (Domini Highsmith, "Frankie" )

Related vocabulary:
[sitting duck]
[feeding frenzy]