The report was so ponderous that it was hard to get through.

ponderous 是形容词，由名词 ponder（意为"沉思、思考"）加上后缀 -ous（表示"充满...的"）构成。字面意思是"充满思考的"，引申为"冗长沉闷的、笨重乏味的"，常用来形容文章或讲话过于冗长、缺乏趣味性。