gun someone down
phrasal verb with gun verb [ T ] mainly US old-fashioned informal uk/ɡʌn/ us/ɡʌn/ -nn-
用枪击伤，击毙（没有防御能力的人）
to shoot someone and kill or seriously injure them, often when that person cannot defend himself or herself
The police officer was gunned down as he took his children to school. 这名警察在送他的孩子去上学时被枪杀。