We don't have synonyms for half siblings yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are half sibling, half-siblings and half-sibling.
(n) :
A sibling sharing a single parent, as distinguished from a full-sibling or sibling-german, from a stepsibling, or from a sibling-like figure such as a blood sibling.
(n) :
(horse racing) Any of two or more horses having the same dam but different sires.
(n) :
A sibling sharing a single parent, as distinguished from a full-sibling or sibling-german, from a stepsibling, or from a sibling-like figure such as a blood sibling.
(n) :
(horse racing) Any of two or more horses having the same dam but different sires.