Final answer:
A synonym for realm is 'domain,' with the realm of programming languages as an example. An antonym for realm could be 'chaos,' as in a realm descending into chaos after the collapse of an empire.
Step-by-step explanation:
The antonym and synonym for realm can be illustrated as follows. A synonym for realm, which refers to a kingdom or a field of interest or activity, might be domain. For example, in the field of software development, coders often discuss the realms or domains of programming languages and their applications. Conversely, an antonym for realm could be chaos, which signifies a lack of order and the opposite of a structured kingdom or field.
An example usage of the synonym might be: 'Quantum physics falls within the realm, or domain, of highly specialized scientific study.' An example usage of the antonym could be: 'With the collapse of the empire, the once orderly realm descended into chaos.'