"Take as gospel truth" is an idiomatic expression that means to believe something without questioning or doubting its validity. Its antonyms, therefore, would be words or phrases that convey the opposite meaning. Some of these antonyms include "doubt," "question," "disbelieve," "challenge," "reject," and "oppose." When we encounter information that seems too good to be true, it's important to approach it with a healthy level of skepticism and critical thinking. By doing so, we can avoid taking anything as gospel truth without first verifying its accuracy and credibility. In today's era of misinformation and fake news, this approach is more important than ever before.