We don't have synonyms for nulla yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are null, bulla and mulla.
(n) :
Alternative form of nullah (“stream-bed, ravine”). [(chiefly South Asia) A stream-bed, ravine, or other watercourse; a drain for rain or floodwater.]
(n) :
Alternative form of nulla-nulla (“Australian war club”). [(Australia) A war club used by Aboriginal Australians]
(n) :
Alternative form of nullah (“stream-bed, ravine”). [(chiefly South Asia) A stream-bed, ravine, or other watercourse; a drain for rain or floodwater.]
(n) :
Alternative form of nulla-nulla (“Australian war club”). [(Australia) A war club used by Aboriginal Australians]