What is the meaning of hostilities?

noun

• Fighting; acts of overt warfare.
  • usage: "the outbreak of hostilities"
  • synonyms: belligerency
• A hostile (very unfriendly) disposition.
  • usage: "he could not conceal his hostility"
  • synonyms: hostility, ill will
• A state of deep-seated ill-will.
  • synonyms: hostility, enmity, antagonism
• The feeling of a hostile person.
  • usage: "he could no longer contain his hostility"
  • synonyms: hostility, enmity, ill will
• Violent action that is hostile and usually unprovoked.
  • synonyms: aggression, hostility