The phrase "fiend for" is an idiomatic expression often used in informal conversations and slang. It is derived from the word "fiend," which typically refers to an individual who is excessively fond of or obsessed with something. When paired with the preposition "for," it emphasizes the intense desire or craving for a particular thing or activity.

As a verb phrase, "fiend for" translates to an insatiable longing or relentless yearning for a specific object, substance, experience, or activity. It conveys a profound passion or addiction towards something, implying that the person has an irresistible and compulsive urge to engage with it habitually or excessively. The phrase is commonly employed to describe an individual's intense enthusiasm or dependency on food, entertainment, hobbies, substances, or even certain individuals.

For instance, one might say "She is a fiend for chocolate," indicating that the person has an overwhelming indulgence for chocolate and frequently seeks it out. Alternatively, "He is a fiend for gaming" suggests that the individual has an insatiable craving for playing video games and spends a significant amount of time engrossed in that activity.

In summary, "fiend for" characterizes a relentless and fervent desire or obsession for a particular thing, representing an individual's insatiable longing or craving that often surpasses normal or healthy levels of interest.