The most common and most likely answer to this crossword clue is the 11 letter word AMERICANISM
I've seen this crossword clue in The Times
A
M
E
R
I
C
A
N
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S
M
More clues leading to the result AMERICANISM
Buddy explains!

The straight part
We know that "24/7, possibly?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case 24/7, possibly? = americanism.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.