take up arms

take up arms (third-person singular simple present takes up arms, present participle taking up arms, simple past took up arms, past participle taken up arms)

1. (intransitive) To prepare to fight; to arm oneself. [with against or for]

   Antonym: lay down one's arms

• “take up arms”, in Merriam-Webster Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.
• “to take up arms”, in Collins English Dictionary.
• “take up arms” (US) / “take up arms” (UK) in Macmillan English Dictionary.