The most common and most likely answer to this crossword clue is the 7 letter word DAMAGES
I've seen this crossword clue in The Guardian
D
A
M
A
G
E
S
More clues leading to the result DAMAGES
- Cost singular to get to Mars
- Barricade, very long, possibly fine
- Mother declines possible award when the action's over?
- Female hackgets legal reparation
- Mother gets on for Mars
- Mother declines sum awarded by court
- A long time after mother’s court award
- Mother loses youth, gets some compensation
- Compensation check matures
- Mars project for a civil engineer with lots of time
Buddy explains!

The straight part
We know that "Mars" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case mars = damages.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 DAMAGES mean?
DAMAGES verb- To impair the soundness, goodness, or value of; to harm or cause destruction.
- To undergo damage.
- The money paid or awarded to a claimant (in England), a pursuer (in Scotland) or a plaintiff (in the US) in a civil action as compensation for a loss suffered by the same.