always go to the fundamentals

competency :: "The combination of observable and measurable knowledge, skills, abilities and personal attributes that contribute to enhanced employee performance and ultimately result in organizational success. "

that is one definition used by one organization. I think it suggests there is no simple easy definition for competency but is a complex algorithm used to measure success.

I'll let the reader decide whether Mr Trump has demonstrated any competence in his current reality show.
ignorance is the enemy
without equality there is no liberty