The most common and most likely answer to this crossword clue is the 7 letter word ERELONG
I've seen this crossword clue in Independent
E
R
E
L
O
N
G
More clues leading to the result ERELONG
- Spanish article about golf catches on soon
- The Sound of Music extended by and by
- Soon lore will be translated into English
- Look to wear green pants soon
- About to engage in base desire soon
- Atmosphere Longfellow captures in no time, poetically
- Without delay, say, loner dashed in
- We are not starting marathon in near future
- Nothing relieves a general disaster soon
- Soon to be given new role in engineering
Buddy explains!

The straight part
We know that "soon" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case soon = erelong.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.