The most common and most likely answer to this crossword clue is the 7 letter word ATTAINT
I've seen this crossword clue in The Times
A
T
T
A
I
N
T
Buddy explains!

The straight part
We know that "loss of rights" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case loss of rights = attaint.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 ATTAINT mean?
ATTAINT noun- A blow or strike, especially in jousting.
- A wound on the leg of a horse caused by a blow
- The giving of a false verdict by a jury; the conviction of such a jury, and the reversal of the verdict
- To subject to attainder; to condemn (someone) to death and extinction of all civil rights.
- To subject to calumny; to accuse of a crime or dishonour.
- To taint; to corrupt, sully.
- Convicted, attainted.
- Attainted; corrupted.