That is to say, he was supposed to be respected as the brother of the future head of the family, but was not necessarily a person the feudatories were loyal to, as he would not inherit his father's property.
つまり家督の近親者としての敬意を払う対象ではあるが、将来的には家督を相続する立場にないため、必ずしも忠誠を尽す対象ではない者を指した語。