The most common and most likely answer to this crossword clue is the 4 plus 4 letter word RUSH HOUR
R
U
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H
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R
More clues leading to the result RUSH HOUR
- Busy period requires routine with no time off, hospitals admitted
- Jam session?
- Bolt, ace, say, not performing in period of heavy activity
- Essentially viruses are contracted at hotel, hospital by men wearing uniform between 9 a.m. and 10 a.m., perhaps
- When arteries may get clogged up?
- Earliest print of hospital 45 minutes after busiest time
- Back-to-back games keeping mum at house busy then
Buddy explains!

The straight part
We know that "between 9 a.m. and 10 a.m., perhaps" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case between 9 a.m. and 10 a.m., perhaps = rush hour.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.
What does RUSH HOUR mean?
RUSH HOUR adjective- Of or pertaining to the rush hour.