There are multiple definitions - click on the translation that matches your context.

kompetencja

rzeczownik

full

competency

noun

Definitions of competency

English

the competency (of a witness) to testify refers to a person's ability to stand trial, especially a criminal defendant

The trial court was satisfied with her competency to testify.

English

the mental ability to understand problems and make decisions

If she really is unable to understand or participate adequately in her own defense then proceedings must be suspended until her competency is restored.