Believable
Part of speech: adjective
Definition: Capable of being believed; credible.
Example sentence: The Marxist theory of ideology is extremely contentious, not least because it is tied to socio-economic hypotheses that are no longer believable.
Credible
Part of speech: adjective
Definition: believable or plausibleauthentic or convincing
Example sentence: The amount of resources we put in are disparate. We put billions of dollars into fuel-efficient technologies. How much are we putting into energy behavior change in a credible, systematic, testing way?