Meaning : The act of imitating the behavior of some situation or some process by means of something suitably analogous (especially for the purpose of study or personnel training).
Meaning : (computer science) the technique of representing the real world by a computer program.
Example :
A simulation should imitate the internal processes and not merely the results of the thing being simulated.
Synonyms : computer simulation
Meaning : Representation of something (sometimes on a smaller scale).
Synonyms : model
Meaning : The act of giving a false appearance.
Example :
His conformity was only pretending.
Synonyms : feigning, pretence, pretending, pretense