The most common and most likely answer to this crossword clue is the 2 plus 3 plus 7 plus 3 plus 6 letter word BE ALL FINGERS AND THUMBS
I've seen this crossword clue in The Guardian
B
E
A
L
L
F
I
N
G
E
R
S
A
N
D
T
H
U
M
B
S
Buddy explains!
The straight part
We know that "Lack coordination" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lack coordination = be all fingers and thumbs.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.