critical

Inclined to find fault or criticize.

A good teacher is fair but critical.

Let us go back to the beginning and consider what the charge is that has made people so critical of me, and has encouraged Meletus to draw up this indictment.

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

This is a critical moment.

Such a scandal as the prosecution of a brother for forgery—with a verdict of guilty—is a most truly horrible, deplorable, fatal thing. It takes the respectability out of a family perhaps at a critical moment, when the family is just assuming the robes of respectability: […] it is a black spot which all the soaps ever advertised could never wash off.

Extremely important.

It's critical that you deliver this on time.

Oxygen levels on Earth skyrocketed 2.4 billion years ago, when cyanobacteria evolved photosynthesis:[…]. The evolutionary precursor of photosynthesis is still under debate, and a new study sheds light. The critical component of the photosynthetic system is the “water-oxidizing complex”, made up of manganese atoms and a calcium atom.

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

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

“Unless you are purchasing cereal from a health food store, many brands that are marketed as healthy are usually full of sugar and processed ingredients,” says Garcia. So when you’re choosing cereal, bread or any other whole-grain product, Garcia recommends reading labels with a critical eye.

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

A critical value, factor, etc.

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

Finally, criticals are high-risk, high-value items that give the final product a competitive advantage in the marketplace […] Criticals, in part, determine the customer's ultimate cost of using the finished product — in our example, the computer.

critical hit

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