Sudden burst of five entering hairdressers' wanting trim (5)
I believe the answer is:
salvo
'sudden burst' is the definition.
(I've seen this in another clue)
'five entering hairdressers' wanting trim' is the wordplay.
'five' becomes 'V' (Roman numeral).
'entering' means one lot of letters goes inside another.
'hairdressers' wanting trim' becomes 'salo' (I can't justify this - if you can you should believe this answer much more).
'v' put into 'salo' is 'SALVO'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for salvo that I've seen before include "Burst of rapid fire" , "Burst of firing" , "Rapid simultaneous discharge of firearms" , "A volley of shots, perhaps as salute" , "Simultaneous artillery fire" .)