The most common and most likely answer to this crossword clue is the 6 letter word ACTIVE
I've seen this crossword clue in The Times
A
C
T
I
V
E
More clues leading to the result ACTIVE
- To perform on stage, I have to be brisk
- Lively grammarian’s voice?
- One of the options for a busy
- Court stops A4e having effect
- Part of play I have shortened, being busy
- Agreement's not quiet - I have to give voice
- Voice last part of play, not loudly
- Empty contract stops A4e having effect
- Lively musical about entertaining clubs
- . Busy disc jockey on ecstasy leaves part of speech
Buddy explains!

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 ACTIVE mean?
ACTIVE noun- A person or thing that is acting or capable of acting.
- Any component that is not passive. See Passivity (engineering).
- Having the power or quality of acting; causing change; communicating action or motion; acting;—opposed to passive, that receives.
- Quick in physical movement; of an agile and vigorous body; nimble.
- In action; actually proceeding; working; in force
- Given to action; constantly engaged in action; energetic; diligent; busy
- Requiring or implying action or exertion
- Given to action rather than contemplation; practical; operative
- Brisk; lively.
- Implying or producing rapid action.
- (heading, grammar) About verbs.
- (of source code) Eligible to be processed by a compiler or interpreter.
- Not passive.
- (gay sexual slang) (of a homosexual man) enjoying a role in anal sex in which he penetrates, rather than being penetrated by his partner.