IshGen 2:3 :ܟܦ݂ܪ ܒܟܪܣܛܝܢܘܬܐ ܘܐܬܓܝܘܪ ‍[‍ܘܐܬܓܙܪ‍]‍ ܐܝܟ ܝܗܘ̈ܕܝܐ‏ : he renounced Christianity and become a proselyte [and was circumcised] like the Jews
See the entire entry for gywr vb. Qt to become a proselyte