What literary device involves comparing two unlike things without using "like" or "as"?

The correct choice, which is metaphor, is a literary device that involves directly comparing two unlike things, suggesting that one embodies characteristics of the other, without using the words "like" or "as." This allows for a deeper connection between the two elements being compared and can create vivid imagery or express a concept more powerfully. For example, saying "Time is a thief" suggests that time steals moments from our lives in a way that highlights the preciousness of time.

Other options include simile, which explicitly makes comparisons using "like" or "as," but does not offer the same depth of connection as a metaphor. Alliteration is the repetition of initial consonant sounds in words close together, which does not serve the function of comparing things. Personification, on the other hand, attributes human characteristics to non-human entities, which is a different approach altogether. Each of these devices plays a unique role in literature, but a metaphor specifically is about making direct, impactful comparisons.