The most common and most likely answer to this crossword clue is the 8 letter word THURSDAY
I've seen this crossword clue in The Times
T
H
U
R
S
D
A
Y
More clues leading to the result THURSDAY
- A sturdy husband strays once a week it appears
- Marshalling yard shut for a time
- Supply yard shut for 24 hours
- 72 hours or so ago, child born then has far to go
- Had rusty wreck on which child will go far?
- Engineer shut yard for some time
- Duty has changed with king being guarded for 24 hours
- Saturday turned out hot for a fourth or fifth day
- Film many drowning in capsized boat around old city quarter
- Yard shut about when in the week?
Buddy explains!

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