The most common and most likely answer to this crossword clue is the 6 letter word BOWING
I've seen this crossword clue in The Daily Telegraph
B
O
W
I
N
G
More clues leading to the result BOWING
Buddy explains!

The straight part
We know that "Leaning/forward" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case leaning/forward = bowing.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 BOWING mean?
BOWING verb- To play music on (a stringed) instrument using a bow.
- To become bent or curved.
- To make something bend or curve.
- To exercise powerful or controlling influence over; to bend, figuratively; to turn; to incline.
- To premiere.
- To bend oneself as a gesture of respect or deference.
- To debut.
- To defer (to something).
- To give a direction, indication, or command to by bowing.
- The act of bending at the waist, as a sign of respect or greeting.
- A bending.
- A technique for using the bow on a string instrument such as a violin.