Indirect anagram

In crossword lore, an indirect anagram is a type of anagram in which a synonym or other subsidiary indication is given partially or wholly as the anagram fodder. This does not include the partial use of abbreviations, a practice normally considered fair in moderation.

Example
Consider the clue Unusually tough monster (5), adapted from an example given in Ximenes on the Art of the Crossword (see History below). Here, the compiler has invoked the indirect anagram: the solver is expected first to find the synonym HARDY for "tough", and then to anagram it to give the answer HYDRA, as opposed to being given the clue Unusually hardy monster (5), in which the letters to be anagrammed are provided literatim.

History
During the formative years of the modern cryptic clue, indirect anagrams were commonplace, with setters as high profile as Afrit and Ximenes routinely using them, even with rare and difficult words; it was not until Ximenes' On the Art of the Crossword was published in 1966 that indirect anagrams began to be widely considered unfair to the solver. He writes (pp. 51-52):
 * Secondly – and here, for once, I differ from Afrit – I hate what I call an indirect anagram. By that I mean "Tough form of monster" for HARDY (anagram of HYDRA). There may not be many monsters in five letters; but all the same I think the clue-writer is being mean and withholding information which the solver can reasonably demand. Why should he have to solve something before he can begin to use part of a clue? He has first to find "hydra" – and why shouldn't it be "giant"? – and then use the anagrammatic information to help him think of "hardy". ... My real point is that the secondary part of the clue – other than the definition – is meant to help the solver. The indirect anagram, unless there are virtually no alternatives, hardly ever does. He only sees it after he has got his answer by other means.

The end result of this controversy is not a global ban on indirect anagrams, but general agreement that they are unfair and excessively difficult, which has led to their disuse in almost all major cryptic crosswords. One notable modern exception and occasional employer of indirect anagrams is Gordius, who sets some of the more difficult crosswords for The Guardian.