The most common and most likely answer to this crossword clue is the 9 letter word OVERDRIVE
I've seen this crossword clue in Financial Times
O
V
E
R
D
R
I
V
E
More clues leading to the result OVERDRIVE
- Top Gear where carport is typically built?
- Without it, Gibson’s 1988 work is just a great picture!
- Finished going up road, I have top gear
- Trim plain tripe in state of heightened activity
- Intense state of activity in terms of cricket?
- Excessive activity across road
- State of heightened activity concerning campaign push
Buddy explains!
The straight part
We know that "Intense state of activity" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case intense state of activity = overdrive.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 OVERDRIVE mean?
OVERDRIVE verb- To drive too hard, or far, or beyond strength.
- A gear, on an automobile, higher than the normal top gear.
- A state of heightened activity.