You have credibility when you seem totally trustworthy or believable. You lose it when you start lying, cheating and acting rather shady.

Credibility is a noun that speaks to plausibility or believableness, so the star witness at your trial or the person writing your recommendation letter should certainly have it. Be careful though, because someone with credibility isn't necessarily telling the truth. As any con man or politician can tell you, credibility can easily come from nothing more than a confident smile.

Definitions of credibility
  1. noun
    the quality of being believable or trustworthy
    synonyms: believability, credibleness
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    incredibility, incredibleness
    the quality of being incredible
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    authenticity, genuineness, legitimacy
    undisputed credibility
    cogency, rigor, rigour, validity
    the quality of being valid and rigorous
    plausibility, plausibleness
    apparent validity
    cred, street cred, street credibility
    credibility among young fashionable urban individuals
    real McCoy, real stuff, real thing
    informal usage attributing authenticity
    reasonableness, tenability, tenableness
    the quality of being plausible or acceptable to a reasonable person
    type of:
    an essential and distinguishing attribute of something or someone
Word Family

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