Wiktionary
a. Without a sister.
Usage examples of "sisterless".
Motherless, sisterless Drou could scarcely have found a more knowledgeable bridal consultant.
For I had been revolving many plans, which had one sole aim and object, to keep near me this lad, whose companionship and help seemed to me, brotherless, sisterless, and friendless as I was, the very thing that would give me an interest in life, or, at least, make it drag on less wearily.
To be with Ethel was perpetual delight--she astonished this sisterless youngster with a thousand feminine niceties and refinements.
Now, Alberich had no more notion of how such things were done than any other sisterless bachelor.
At the back of his head he had that fear of women as something mysterious and unintelligible which belongs to a motherless and sisterless childhood, and a youth spent almost wholly in the company of men.
He was all the world to me, for I was alone, an orphan, sisterless and brotherless.
Alys Vorpatril was widely acknowledged as the premier social arbiter of Vorbarr Sultana, not least because of her frequent duties at the Imperial Residence as official welcomer for wifeless, motherless, sisterless Emperor Gregor.
Enveloped in a moral atmosphere at once bracing and tender from her childhood upwards, it had never occurred to her to regret that she was not only orphaned, but sisterless and brotherless as well, in the ordinary acceptation of the phrase.
And, of course, that infant would be the heir to the throne if he or she was born brotherless and sisterless into the world.