The most common and most likely answer to this crossword clue is the 8 letter word EXECRATE
I've seen this crossword clue in The Daily Telegraph
E
X
E
C
R
A
T
E
More clues leading to the result EXECRATE
- Condemn CEO’s salary?
- Condemn directors’ pay scale?
- Condemn the amount managers are paid?
- Condemn river vehicle that’s worn out
- Curse West Country river case
- Deplore judge supporting senior manager
- European in old bus can't stand
- Denounce what senior management get paid?
- Condemn cost of employing manager?
- Despise boss a certain amount
Buddy explains!

The straight part
We know that "Damn" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case damn = execrate.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 EXECRATE mean?
EXECRATE verb- To feel loathing for; to abhor
- To declare to be hateful or abhorrent; to denounce
- To invoke a curse; to curse or swear