"Shut yourself off" is an expression that refers to secluding oneself from the rest of the world. Synonyms for this phrase include disconnect, isolate, withdraw, retreat, and seclude oneself. Disconnect refers to cutting off communication or contact with others. Isolate means separating oneself from others who might be mentally or physically challenging to cope with. Withdraw means to retreat from society or to step back from certain situations. Retreat refers to withdrawing from a specific environment to seek refuge. Seclude oneself refers to separating oneself from others to improve mental health or to seek solitude. These words can be helpful to use when one wants to express the act of seclusion without using the same word repeatedly.