徹てっ底てい究きゅう明めい

noun

thorough investigation; complete inquiry

Used for exhaustive probing or getting to the bottom of a matter, often in formal or serious contexts such as accidents, scandals, or research.

• 事じ故この原げん因いんを徹てっ底てい究きゅう明めいする必ひつ要ようがある。

  We need to conduct a thorough investigation into the cause of the accident.

• 委い員いん会かいは問もん題だいの徹てっ底てい究きゅう明めいを約やく束そくした。

  The committee promised a complete inquiry into the issue.