The most common and most likely answer to this crossword clue is the 9 letter word CONSCIOUS
I've seen this crossword clue in The Guardian
C
O
N
S
C
I
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S
More clues leading to the result CONSCIOUS
- Mindful of concussion? Not entirely bothered
- Aware of prisoner’s constant promises to pay
- Deceives many with promises? That’s deliberate!
- Deceives with many promises? That’s deliberate!
- Aware of Conservative’s debts after constituent’s tip
- Aware of carbon monoxide above scatter cushions husband removed
- Aware of coins circulating in Colorado and all over United States
- After company, disturbed cousins may be awake
Buddy explains!

The straight part
We know that "deliberate" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case deliberate = conscious.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 CONSCIOUS mean?
CONSCIOUS noun- The part of the mind that is aware of itself; the consciousness.
- Alert, awake; with one's mental faculties active.
- Aware of one's own existence; aware of one's own awareness.
- Aware of, sensitive to; observing and noticing, or being strongly interested in or concerned about.
- Deliberate, intentional, done with awareness of what one is doing.
- Known or felt personally, internally by a person.
- Self-conscious.