Which statement best defines a metaphor?

A metaphor is defined as a direct comparison of two different things without using the words "like" or "as." This means it asserts that one thing is another, helping to illustrate a point or convey an idea more vividly. For example, saying "Time is a thief" directly suggests that time, like a thief, steals moments from our lives, creating a strong image and deeper understanding.

In contrast, the other options present different literary devices. The first choice describes a simile, which does use "like" or "as" to make comparisons. The third choice refers to hyperbole, which is an exaggerated statement not meant to be taken literally. Lastly, the fourth option describes a rhetorical question, which is designed to provoke thought rather than create a direct comparison. Thus, the definition of a metaphor succinctly captures the essence of this literary device, making the chosen answer accurate.