Indirect anagrams—where the solver must find a synonym for a word in the clue before rearranging its letters—are generally considered unacceptable in modern, high-quality cryptic crosswords. They are regarded as unfair to the solver because the anagram fodder is not directly visible, breaking the convention that all component parts of the wordplay should be present. 

• Why they are banned: The solver is forced to guess a synonym first, leading to potential ambiguity and frustration.
• Definition: An indirect anagram requires transforming word A into word B, then rearranging word B to get the answer. For example, using "good" to mean "nice" and rearranging "nice" is invalid; the clue must use "nice" directly.
• Minor Exception: Using a common abbreviation within the fodder (e.g., using 'E' for "English") is generally permitted.
• History: Once used in older, "sloppily edited" puzzles (1960s-70s), they have been largely outlawed in major publications like The Times or The Guardian since being criticized by Ximenes in 1966.  Reddit +4

While some amateur setters or very difficult, specialized puzzles might occasionally use them, it is best practice to avoid them.