The most common and most likely answer to this crossword clue is the 11 letter word INDIGNATION
I've seen this crossword clue in The Daily Telegraph
I
N
D
I
G
N
A
T
I
O
N
More clues leading to the result INDIGNATION
Buddy explains!
The straight part
We know that "anger" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case anger = indignation.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does INDIGNATION mean?
INDIGNATION noun- An anger aroused by something perceived as an indignity, notably an offense or injustice.
- A self-righteous anger or disgust.