Final answer:
The rhetorical device used in the given phrases is a euphemism, which is a more polite or less direct expression used in place of harsh or direct language.
Step-by-step explanation:
The rhetorical device used in the phrases “Sanitation engineer”, “Pre-owned vehicle”, and “Economically disadvantaged” is known as euphemism. A euphemism is a figure of speech where a more gentle or less direct word or expression is used in place of another word or phrase that might be considered harsh, blunt, or unpleasant. It is a way to communicate more sensitive content or to soften the impact of straightforward language.
These terms express the same ideas as “garbage collector”, “used car”, and “poor” but do so in a way that can feel more polite or less offensive. Euphemisms are often used in everyday language, marketing, and political communication.
Euphemisms apply to multiple aspects of language and are a testament to the power words have on perception and demeanor. They can redirect thought, provide comfort, and avoid confrontation. They are used across various fields, including business, health, and social interactions, to convey messages with a softer impact.