nark

Noun

• a lawman concerned with narcotics violations

• an informer or spy working for the police

Verb

• inform or spy (for the police)

• cause annoyance in; disturb, especially by minor irritations
  • Mosquitoes buzzing in my ear really bothers me
    
  • It irritates me that she never closes the door after she leaves
    

Related words

• Synonyms: 
  narc , narcotics agent , copper's nark