Kajirus is the common expression for a male slave. The plural for slaves considered together, both male and female, or for more than one male slave is kajiri.
"'Yes, Master,' he said. This was a play, of course, on the common Gorean saying that curiosity is not becoming in a female slave, or kajira. One of the traces of Earth influence on Gorean, incidentally, in this case, an influence from Latin, occurs in the singular and plural endings of certain expressions. For example, 'kajirus' is a common expression in Gorean for a male slave as is 'kajira' for a female slave. The plural for slaves considered together, both male and female, or for more than one male slave is 'kajiri'. The plural for female slaves is 'kajirae'." --Magicians of Gor, page 529-530
NOTICE: There are many versions of the Gorean Saga books in many languages. Because of this, page numbers are not always the same from version to version. All quotes on this website are from the English, print version published by E-Reads commemorating the 40th anniversary of the first book, Tarnsman of Gor.