imperative
n.n. extremely important or urgent. You use this when something must be done immediately and cannot be ignored.
n. expressing a command or an absolute necessity. Often describes an action that is vital for the success or survival of a project or person.
It is imperative that you finish this report today.
In the middle of a medical emergency, it is imperative to remain calm and follow the doctor's instructions exactly.
While the financial costs are significant, the moral imperative to protect the environment for future generations outweighs any short-term economic concerns the board might have.
Borrowed from Latin imperātīvus.
Often used in the pattern 'it is imperative that...' followed by a clause in the subjunctive or with 'should'.
It is imperative for you finishIt is imperative that you finishWhen followed by a clause, this word requires 'that' and a subject, not an infinitive with 'for'.