"To block the takeover" means to take actions or make efforts to prevent another person, company, or group from gaining control or power over something. Full definition
Nassau County Executive Ed Mangano is suing a state board in hopes of blocking its takeover of county finances. (nystateofpolitics.com)
Last week, CNBC reported the Justice Department could sue to block the takeover unless AT&T agrees to sell its DirecTV division or Time Warner's Turner Broadcasting, which owns CNN. (cnbc.com)
The Trump administration, for instance, recently blocked the takeover bid of U.S company Qualcomm by the Singapore - based Broadcom, on national security grounds. (recode.net)