The most common and most likely answer to this crossword clue is the 1 plus 4 plus 2 plus 3 plus 5 letter word A DROP IN THE OCEAN
I've seen this crossword clue in The Daily Telegraph
A
D
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N
More clues leading to the result A DROP IN THE OCEAN
- Insignificant event preceding tsunami
- Hardly any at low tide?
- Insignificant part of the whole Mariana Trench?
- Indian descent possibly of little consequence
- Maybe cheaper donation makes no difference
- 19’s fate, uncharacteristically!
- Very little indeed of what some returning astronauts anticipated?
- A fall in sea level is something insignificant
- Drink for a drifter? It’ll have no great effect
- Ditching a trifle?
Buddy explains!
The straight part
We know that "what some returning astronauts anticipated" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case what some returning astronauts anticipated = a drop in the ocean.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.