› to decide officially to stop something from happening or continuing: The federal government's fight to block a bankruptcy settlement was rejected by the Supreme Court.block a bid/deal/merger The Federal Trade Commission said it planned to block the merger.
› BANKING if a bank blocks someone's account, they make it impossible for that person to remove money from it: Accounts of all suspected terrorists have been blocked.
› COMMUNICATIONS to stop emails, text messages, phone calls, etc. from a particular person: The new phone allows users to block messages from particular senders.