How should words be defined?

In a Nutshell: Terms can be defined in a number of ways ranging from lexically, stipulatively, intensionally, extensionally and ostensively. Understanding the meaning of different terms is aided by a good definition. But what constitutes a good definition? To answer this, try to consider the five types of standard definitions that exist and pick the appropriate one for the context of your discussion. 1. Lexical definitions Often termed linguistic definitions, these attempt to put down the usage of a term, how native speakers use words in their various senses. Dictionary definitions are typically lexical in nature. 2. Stipulative definitions Sometomes labelled technical or specialist definitions, these stipulate what a word or phrase means often introducing new terms or giving a new meaning for existing terms.  3. Intensional definitions Intensional definitions cite the properties which applies to all members of that term and to nothing else. A chemist might provide an intensional definition of a chemical, whilst a theologian might define God intensionally. 4. Extensional definitions Extensional definitions provide a list of all the items to which the term applies. For example, the term "seven deadly sins" is defined extensionally by citing all of the seven deadly sins. In contrast, an intensional definition might define them as those acts that lead one to eternal torment or damnation. 5. Ostensive definitions These sorts of definitions explain the meaning of a term by usually providing a small sample of the things covered by the term. One may define the term "humble" ostensively by listing humble acts and behavior. Ostensive definitions can be unclear in contrast to extensional definitions as the latter provides the complete extension of a term leaving minimal space for misinterpretations, whilst the former provides only a sample leaving greater room for error in understanding. Given some concepts are pretty complex making extensional definitions difficult to formulate, one can only put forward an ostensive definition. Conclusion Terms can be defined in a number of ways ranging from lexically, stipulatively, intensionally, extensionally and ostensively.