Cheerleader's routine (4)
I believe the answer is:
yell
'cheerleader's routine' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for yell that I've seen before include "Shout loudly" , "roar" , "Give a sudden loud cry" , "Shout - Shetland island" , "Bawl, yowl" .)