Learn how to say Sidearms correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word sidearm:
a weapon worn at a person’s side, such as a pistol or formerly a sword.
(of a throw, pitch, or cast) performed or delivered with a sweeping motion of the arm from the side of the body at or below shoulder level:
a sidearm delivery
I could throw sidearm
[with object] chiefly Baseball
throw or pitch a ball to (someone) with a sidearm motion:
pitchers who sidearmed me on one pitch, then curved me with the next
throw or pitch (a ball or other object) with a sidearm motion:
he sidearmed a small stone, which missed the bottle