expression, adverb
unfavorably; disparagingly; in a bad light
Used when speaking or writing about someone or something in a negative, critical, or insulting way. Often paired with verbs like 言う, 書く, 評する.
彼はいつも人のことを悪し様に言う。
He always speaks ill of others.
新聞はその事件を悪し様に書いた。
The newspaper wrote about the incident in a disparaging way.
悪口 is a noun meaning 'badmouthing' or 'abuse', while 悪し様に is an adverbial phrase describing the manner of speaking negatively.
けなす is a verb meaning 'to speak ill of' or 'to disparage', whereas 悪し様に modifies how something is said or written.
From 悪し (archaic form of 悪い, 'bad') + 様 (ざま, 'manner') + に (adverbial particle). The phrase literally means 'in a bad manner'.