Fiend for is a phrase used to describe a strong desire or addiction to something. There are several synonyms that can be used to replace this phrase in conversation or writing. One popular option is "craving," which refers to a strong desire for something, often a specific food or drink. Additionally, "obsessed with" or "addicted to" can be used to convey a strong attachment to a particular activity or substance. Another option is "fanatic," which suggests a deep devotion or enthusiasm for a specific interest or hobby. By using these synonyms, you can express your thoughts and feelings more precisely, creating a more impactful message.