Which figure of speech compares two unlike things without using "like" or "as"?

A metaphor is a figure of speech that makes a direct comparison between two unlike things by stating that one thing is another, thereby highlighting a particular quality or aspect they share. This comparison does not use "like" or "as," which distinguishes it from a simile, which does make such comparisons using those words.

For example, saying "time is a thief" suggests that time steals moments from our lives, similar to how a thief would take valuables. This illustrates a sense of loss and urgency without explicitly stating how time is similar to a thief in a literal sense. This direct comparison allows for a deeper understanding and appreciation of the idea being expressed.

In contrast, a simile would say "time is like a thief," clearly indicating a comparison rather than a direct identification. Personification involves giving human traits to non-human entities, while an analogy is a more complex comparison that explains one idea or thing in terms of another to enhance understanding but is not structured like a metaphor. Thus, the nature of metaphor makes it a powerful and concise way to convey meaning about the relationship between different concepts.