From Hebrew
It means someone who is high
Person to high friend: "dude are you patsuts?"
High friend: "haha yeah"
From Arabic meaning sane, it is used as a Hebrew slang for someone who is alcohol or drugs free , or if he acts like someone who is alcohol or drug free.
Sachi can be used as a personality trait for someone.
"hey are you smoking tonight?"
"Nah I'm a Sachi today I got work tommorow"
Or
Person 1: "Duude I'm Soo drunk I drank like 15 shots"
Person 2: "Bro no one cares you're such a Sachi"