مؤثر

Of crucial importance in relation to the development or success of something else. It describes something that acts as a center or a main turning point.

The state of being completely absorbed or immersed in something, or the duration it takes for something to happen.

Being the only one of its kind; unlike anything else. It describes something exceptional, unique, or peerless.

A hurdle or obstacle that prevents progress or makes it difficult. Often used in TOEFL to describe challenges in scientific research or historical progress.

A general direction in which something is developing or changing; an inclination or trend.

A remark expressing an opinion or reaction, or the act of suspending something. In TOEFL, it can refer to a professor's commentary or the suspension of a policy.

Very unusual, special, or out of the ordinary; exceeding common standards.

To take place, occur, or come about. It is used to describe an event or a change happening in time.

Clearly defined or identified. It refers to something specific, fixed, or precise rather than general.

The course of someone's life or career. It can also refer to a long walk, march, or procession.