truthful

/ˈtruθfəl/

/ˈtruθfʊl/

Truthful means honest or believable. A truthful answer to a question doesn't mince words—it is completely straightforward and accurate.

If your little sister asks you whether the Tooth Fairy is real, you'll have to consider how truthful you want to be. You can think about whether the truthful answer will be to upsetting for her, since you're not under oath in a courtroom, where you're legally obligated to be truthful. A now-obsolete adjective with the same meaning was truthy, "characterized by truth."

Definitions of truthful

1. adjective

   expressing or given to expressing the truth
   “gave truthful testimony”

   “a truthful person”

   synonyms: true

   honest, honorable

   not disposed to cheat or defraud; not deceptive or fraudulent

   honest

   marked by truth

   veracious

   habitually speaking the truth

   antonyms:

   untruthful

   not expressing or given to expressing the truth

   dishonest, dishonorable

   deceptive or fraudulent; disposed to cheat or defraud or deceive

   mendacious

   given to lying
2. adjective

   conforming to truth
   “a truthful statement”

   synonyms:

   true

   consistent with fact or reality; not false