na-adjective, noun
confused; inconsistent; incoherent; patchy
Describes something that is a jumble of disparate elements, lacking coherence or consistency. Often used for ideas, arguments, collections, or knowledge. Slightly formal and literary.
彼の説明は雑駁で、何が言いたいのかわからなかった。
His explanation was confused and I couldn't understand what he wanted to say.
この本
This book's content is patchy and not systematically organized.
Standard kanji spelling.
Mixed kana-kanji spelling; 駁 is a non-jōyō kanji, so this form is sometimes used for readability.
Compound of 雑 (ざつ, miscellaneous, mixed) and 駁 (ばく, refute, contradict, patchy). The reading ざっぱく results from rendaku voicing of はく to ぱく. The word describes a state of being a confused mixture of various things.