IPA: /ˈɡræp.lər/
KK: /ˈgræplər/
A person who engages in wrestling or grappling, often in a competitive or sports context.
The grappler trained hard every day to improve his skills for the upcoming tournament.
Grappler → It is formed from "grapple" (from Old French *grappler*, meaning to seize or grasp) and "-er" (meaning a person who). A grappler is a person who seizes or engages in grappling, a form of wrestling or combat.
Think of someone who 'seizes' or 'grabs' ('grapple') in a wrestling match — that's why a grappler is a person who engages in this kind of fighting.