The most common and most likely answer to this crossword clue is the 6 letter word DETAIN
D
E
T
A
I
N
More clues leading to the result DETAIN
- Arrest Greek character involved in racket
- Keep fish in private room
- Keep exotic fish in private room
- Hold back Greek character during row
- Outcry over nationalist group’s arrest
- Abandon rail transport, losing heart with delay
- Get out onto platform, but missing right stop
- Delay by putting the date in wrongly
- Arrest Greek character involved in row
- Make late noise, drowning English cheers
Buddy explains!

The straight part
We know that "Keep" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case keep = detain.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 DETAIN mean?
DETAIN verb- To keep someone from proceeding by holding them back or making claims on their attention.
- To put under custody.
- To keep back or from; to withhold.
- To seize goods for official purposes.