critical

Inclined to find fault or criticize.

• A good teacher is fair but critical.

Pertaining to, or indicating, a crisis or turning point.

• This is a critical moment.

Extremely important.

• It's critical that you deliver this on time.

Relating to criticism or careful analysis, such as literary or film criticism.

• The movie was a critical success, but bombed at the box-office.

Relating to criticism or careful analysis, such as literary or film criticism.; Employing or related to textual criticism, particularly through a stemmatological comparison of all extant texts and reconstruction of the original.

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.

In such a condition.broadly

• The patient is critical.
• Two critical after fatal Wimbledon school crash

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.

Of the point (in temperature, reagent concentration etc.) where a nuclear or chemical reaction becomes self-sustaining.

• The reaction was about to become critical.

Of a temperature that is equal to the temperature of the critical point of a substance, i.e. the temperature above which the substance cannot be liquefied.

A critical value, factor, etc.

• The second undamped system criticals show a greater percentage depression than the first.

critical hit

In breakdancing, a kind of airflare move in which the dancer hops from one hand to the other.