The most common and most likely answer to this crossword clue is the 7 letter word OPENING
I've seen this crossword clue in The Guardian
O
P
E
N
I
N
G
More clues leading to the result OPENING
- Opportunity created by old writer in Greek capital
- Round figure doctor holds up in window, perhaps
- Rent for which eg nine pounds raised more than enough
- Old writing, wanting a new start
- Opportunity to play in championship finally gone
- First hole
- Gap garment a third off — over nine grand!
- Initial opportunity
- Supposing one’s knocked out by Earth’s opportunity?
- Love writing, but missing a new opportunity
Buddy explains!

The straight part
We know that "opportunity" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case opportunity = opening.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 OPENING mean?
OPENING verb- To make something accessible or allow for passage by moving from a shut position.
- To make (an open space, etc.) by clearing away an obstacle or obstacles, in order to allow for passage, access, or visibility.
- To bring up, broach.
- To enter upon, begin.
- To spread; to expand into an open or loose position.
- To make accessible to customers or clients.
- To start (a campaign).
- To become open.
- To begin conducting business.
- To begin a side's innings as one of the first two batsmen.
- To bet before any other player has in a particular betting round in a game of poker.
- To reveal one's hand.
- (of a file, document, etc.) To load into memory for viewing or editing.
- To disclose; to reveal; to interpret; to explain.
- An act or instance of making or becoming open.
- Something that is open.
- An act or instance of beginning.
- Something that is a beginning.
- A vacant position, especially in an array.
- An opportunity, as in a competitive activity.
- In mathematical morphology, the dilation of the erosion of a set.
- Pertaining to the start or beginning of a series of events.
- Describing the first period of play, usually up to the fall of the first wicket; describing a batsman who opens the innings or a bowler who opens the attack