Umpire
Noun
るいしん
あの一塁の塁審、試合中に屁をこきまくってたぜ。
The umpire at first base kept farting during the game.
A baseball base judge is one who judges things on a baseball field. This is a baseball umpire, or more simply, an umpire.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.