The most common and most likely answer to this crossword clue is the 8 letter word REPENTED
I've seen this crossword clue in The Daily Telegraph
R
E
P
E
N
T
E
D
More clues leading to the result REPENTED
Buddy explains!

The straight part
We know that "Was ashamed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case was ashamed = repented.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 REPENTED mean?
REPENTED verb- To feel pain, sorrow, or regret for what one has done or omitted to do; the cause for repenting may be indicated with "of".
- To be sorry for sin as morally evil, and to seek forgiveness; to cease to practice sin and to love.
- To feel pain on account of; to remember with sorrow.
- To be sorry for, to regret.
- To cause to have sorrow or regret.
- To cause (oneself) to feel pain or regret.