The most common and most likely answer to this crossword clue is the 10 letter word BEFOREHAND
I've seen this crossword clue in The Daily Telegraph
B
E
F
O
R
E
H
A
N
D
More clues leading to the result BEFOREHAND
- Come to pass with tennis stroke in advance
- Live tennis shot in advance
- Stroke heads of beagles eagerly advancing in anticipation
- Teaching graduate embracing Chinese after a word of warning in advance
- Sort of beer labourer gets in advance
- Earlier, in front of worker
- Live? Shot previously
- Ben heard of riots in advance
- Earlier group full of energy loudly followed by rising idol
Buddy explains!

The straight part
We know that "previously" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case previously = beforehand.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 BEFOREHAND mean?
BEFOREHAND adjective- In comfortable circumstances as regards property; forehanded.
- (often followed by with) In a state of anticipation or preoccupation.
- At an earlier or preceding time.