The most common and most likely answer to this crossword clue is the 9 letter word ANDANTINO
I've seen this crossword clue in The Guardian
A
N
D
A
N
T
I
N
O
More clues leading to the result ANDANTINO
- Moreover, nation developed at a slowish pace
- Noted piece in article chap can ring
- With one against playing back slow piece of music
- Two articles about daughter into running quite slowly
- Movement – see nanna do it awkwardly
- Mark in time a new dawn’s dawn: nation reformed
- An older relative can ring about daughter moving rather slowly
- Against embarking on ‘Donna’at a measured pace?
- Movement seen in Scotland – Antinomianism?
- TV presenters Dec ___ in love, moving quite slowly
Buddy explains!

The straight part
We know that "quite slowly" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case quite slowly = andantino.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 ANDANTINO mean?
ANDANTINO adverb- Of a tempo that is slightly faster than andante but slower than moderato.