The most common and most likely answer to this crossword clue is the 5 letter word WHOOP
W
H
O
O
P
Buddy explains!

The straight part
We know that "a scream" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a scream = whoop.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 WHOOP mean?
WHOOP noun- A loud, eager cry, usually of joy.
- A gasp, characteristic of whooping cough.
- A bump on a racetrack.
- To make a whoop.
- To shout, to yell.
- To cough or breathe with a sonorous inspiration, as in whooping cough.
- To insult with shouts; to chase with derision.
- To beat, to strike.
- To defeat thoroughly.