When do you call a definition a good definition?

Answer 1

A "good" definition is one that adequately explains the meaning and use of the word or term.

Here are some attributes of a good definition of "X.":

1) It does not include any of the words in "X.", nor their synonyms.

2) It admits all possible Xs.

3) It excludes all entities that are not Xs.

4) It is as short as possible while still doing all of the above..

5) It uses the simplest and most familiar words.

6) It is understood by the people who need to use it.