A news report's impact depends heavily on the credibility of its source.

credibility 是由形容词 credible（可信的）加上名词后缀 -ity 构成的名词，表示"可信度、可靠性"。credible 来自拉丁词根 cred（相信），所以 credibility 字面意思是"可被相信的程度"。