불가결하다

Having great importance, significance, or consequence; critical.

A strong point, advantage, or beneficial feature of something or someone.

A weak point, disadvantage, or flaw of something or someone.

To be required or demanded as a necessary condition or action.

To correspond to, be applicable to, or fall under a certain category or value.

To be insufficient, lacking, or not enough in quantity, quality, or ability.

The center of interest or activity; the point where light rays meet (optics). In discussion, it refers to the main point of concentration.

The physical or mental energy that is exerted to achieve a purpose or result.

A cause, explanation, or justification for an action or event.

Relating to or concerned with what is actually possible or likely in a given situation, rather than what is ideal or imagined.