You can then extensionally define "renate" as "has a spinal column"

But what "renate" means intensionally has to do with kidneys, not spines.

I don't think this has been covered here yet, so for those not familiar with these two terms: inferring something extensionally means you infer something based on the set in which an object belongs to. Inferring something intensionally means you infer something based on the actual properties of the object.

Wikipedia formulates these as

An extensional definition of a concept or term formulates its meaning by specifying its extension, that is, every object that falls under the definition of the concept or term in question.

For example, an extensional definition of the term "nation of the world" might be given by listing all of the nations of the world, or by giving some other means of recognizing the members of the corresponding class.*

and

an intensional definition gives the meaning of a term by specifying all the properties required to come to that definition, that is, the necessary and sufficient conditions for belonging to the set being defined.

For example, an intensional definition of "bachelor" is "unmarried man." Being an unmarried man is an essential property of something referred to as a bachelor. It is a necessary condition: one cannot be a bachelor without being an unmarried man. It is also a sufficient condition: any unmarried man is a bachelor

Rule of thumb in case you get forget which is which: EXTEnsion refers to "external" properties, like the group you happen to belong into, while INTEnsion refers to internal properties.