The most common and most likely answer to this crossword clue is the 4 letter word HURL
H
U
R
L
More clues leading to the result HURL
Buddy explains!

The straight part
We know that "Cast" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cast = hurl.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 HURL mean?
HURL noun- A throw, especially a violent throw; a fling.
- The act of vomiting.
- The act of hitting the sliotar with the hurley.
- A conveyance in a wheeled vehicle; a ride in a car, etc.
- Tumult; riot; hurly-burly
- A table on which fibre is stirred and mixed by beating with a bow spring.
- To throw (something) with force.
- To utter (harsh or derogatory speech), especially at its target.
- To participate in the sport of hurling.
- To vomit.
- To twist or turn.
- To move rapidly with a noise; to whirl.
- To convey in a wheeled vehicle.