The most common and most likely answer to this crossword clue is the 8 letter word CHORUSES
I've seen this crossword clue in The Daily Telegraph
C
H
O
R
U
S
E
S
Buddy explains!

The straight part
We know that "Refrains" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case refrains = choruses.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 CHORUSES mean?
CHORUSES noun- A group of singers and dancers in the religious festivals of ancient Greece.
- A group of people in a play or performance who recite together.
- A group of singers; singing group who perform together.
- A repeated part of a song.
- The improvised solo section in a small group performance.
- A setting or feature in electronic music that makes one voice sound like many.
- A group of people or animals who make sounds together
- The noise made by such a group.
- An actor who reads the opening and closing lines of a play.
- To sing or recite in chorus.
- To say in unison; to express in unison.
- To echo (a particular sentiment).
- To sing the chorus (of a song).
- To speak as if in chorus (about something).
- To echo in unison another person's words.
- (of animals) To make their cry together.