crucial (adj)

Her work has been crucial to the project's success.
It is crucial that the problem is tackled immediately.
The timely intervention of the paramedics was crucial in saving the accident victim's life.
The negotiations played a crucial role in establishing diplomatic relations between the two countries.
Attention to detail is crucial when conducting scientific experiments to ensure accurate and reliable results.
The success of the project hinged on the team's ability to meet the crucial deadline set by the client.