adjective Pertaining to, or indicating, a crisis or turning point.
This is a critical moment.
adjective Extremely important.
It's critical that you deliver this on time.
adjective Relating to criticism or careful analysis, such as literary or film criticism.
The movie was a critical success, but bombed at the box-office.
adjective Employing or related to textual criticism, particularly through a stemmatological comparison of all extant texts and reconstruction of the original.
adjective Of a patient condition involving unstable vital signs and a prognosis that predicts the condition could worsen; or, a patient condition that requires urgent treatment in an intensive care or critical care medical facility.
The patient's condition is critical.
adjective In such a condition.
The patient is critical.
adjective Likely to go out of control if disturbed, that is, opposite of stable.
The political situation was so critical that the government declared the state of siege.