戒刀

Buddhist monk's knife (not used for killing)

knife / blade / single-edged sword / cutlass / CL:把[ba3] / (slang) dollar (loanword) / classifier for sets of one hundred sheets (of paper) / classifier for knife cuts or stabs

to guard against / to exhort / to admonish or warn / to give up or stop doing sth / Buddhist monastic discipline / ring (for a finger)