The most common and most likely answer to this crossword clue is the 3 plus 4 letter word NEW MOON
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More clues leading to the result NEW MOON
- Crazed women about when nights are darkest?
- Submariner prepared to receive onset of water in dark period
- Women off and on in vision at night
- Was familiar with, reportedly, parameters of Mornington Crescent
- 12 embraces partners getting married — a regular occurrence
- Women moving forward in emergent body
- Women bent on heavenly body being seen afresh
- Night light women switched on
- Celestial phenomenon with flash in gas
- View of satellite? No sign, looking back around West
Buddy explains!

The straight part
We know that "Crescent" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case crescent = new moon.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.