The most common and most likely answer to this crossword clue is the 7 letter word WARBLER
W
A
R
B
L
E
R
More clues leading to the result WARBLER
- Singer with broken barrel
- Conflict when graduate met royal soprano
- During quarrel bra worries backing singer
- Flyer fighting the French in the outskirts of Barfleur
- Upset Rod and Aleem, initially split on pad-first dismissal
- Brawler knocked about
- Point to barrel-shaped singer
- Fats changes first line to R ‘n’ B for songster
- Singer‘s unseemly brawl in front of English rabbi
- Type of bird whistle
Buddy explains!

The straight part
We know that "songster" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case songster = warbler.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 WARBLER mean?
WARBLER noun- Any of various small passerine songbirds, especially of the family Sylviidae (Old World warblers) and Parulidae (New World warblers).
- One who warbles.
- A hissy fit.