The most common and most likely answer to this crossword clue is the 9 letter word GALUMPHED
I've seen this crossword clue in The Times
G
A
L
U
M
P
H
E
D
Buddy explains!
The straight part
We know that "lumbered" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lumbered = galumphed.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 GALUMPHED mean?
GALUMPHED verb- To move heavily and clumsily, or with a sense of prancing and triumph.