The most common and most likely answer to this crossword clue is the 9 letter word DISMISSAL
I've seen this crossword clue in The Times
D
I
S
M
I
S
S
A
L
More clues leading to the result DISMISSAL
- Rejection upset boy -- is young lady hiding?
- Gloomy about one’s son’s expulsion
- Release detective's service details in printed form
- One’s given spades in awful cards
- Gloomy about one’s son’s sacking
- Girl's church book found in the sack
- Is girl embraced by boy about to get the sack?
- Sacking is stored at first with poor quality cover
- Notice society girl wearing ring
- Is music centre occupying sad sack?
Buddy explains!

The straight part
We know that "Release" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case release = dismissal.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 DISMISSAL mean?
DISMISSAL noun- The act of sending someone away.
- Deprivation of office; the fact or process of being fired from employment or stripped of rank.
- A written or spoken statement of such an act.
- Release from confinement; liberation.
- Removal from consideration; putting something out of one's mind, mentally disregarding something or someone.
- The rejection of a legal proceeding, or a claim or charge made therein.
- The event of a batsman getting out; a wicket.