deadly

adjective
  1. Causing or capable of causing death. adjective
    The venom of the snake is deadly to humans.
    He was found guilty of using a deadly weapon during the robbery.
  2. Extremely accurate or effective. adjective
    Her aim with the bow and arrow was deadly.
    The striker's deadly precision in front of the goal made him a top scorer.
  3. Very intense or extreme. adjective
    There was a deadly silence after the announcement.
    The competition was deadly serious, with no room for error.
  4. In a way that is likely to cause death. adverb
    The poison acts deadly when ingested.
    The virus spread deadly throughout the community.