We don't have synonyms for polwarth yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are howarth, holzwarth and polyarch.
(n) :
A sheep of a rather large medium-wooled Australian breed, developed from crosses of Merino and Lincoln sheep and noted for ability to withstand damp and cold.
(n) :
A sheep of a rather large medium-wooled Australian breed, developed from crosses of Merino and Lincoln sheep and noted for ability to withstand damp and cold.