The most common and most likely answer to this crossword clue is the 10 letter word FRIENDLILY
I've seen this crossword clue in The Guardian
F
R
I
E
N
D
L
I
L
Y
Buddy explains!
The straight part
We know that "Amicably" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case amicably = friendlily.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 FRIENDLILY mean?
FRIENDLILY adverb- In a friendly manner; like a friend; warmly; kindly.