The tech support team was completely non-responsive to the urgent emails, which was very disappointing.

non-responsive 是由前缀 non-（表示“非、不”）和形容词 responsive（“有反应的”）组成的复合形容词。responsive 来自动词 respond（“回应”），加上后缀 -ive 构成形容词。non-responsive 字面意思是“没有回应的”，指“毫无反应的、不响应的”。