scathingly

This adverb conveys a level of criticism that is not merely negative but intended to wound or devastate the subject. It suggests a sharp, biting quality, often associated with intellectual or professional demolition, where the speaker uses precise, cutting language to expose flaws.

In terms of register, it is most frequently found in formal writing, literary criticism, or journalistic reviews. It is rarely used in casual conversation, where words like "harshly" or "brutally" would be more natural. The term implies a certain level of sophistication or authority in the delivery of the critique.