vociferant

/voʊˈsɪfərənt/
adjective
  1. Making a loud, forceful, or vehement outcry; shouting or protesting noisily.
    • A vociferant protester was escorted from the building.
    • The vociferant crowd demanded the mayor's resignation.
    • Her vociferant complaints could be heard throughout the office.
Antonyms
noun
  1. A person who shouts or protests loudly and forcefully.
    • Among the group, the loudest vociferant was a young student.
    • The vociferants were quickly silenced by the security team.
    • The debate hall was filled with vociferants from both sides.