We don't have synonyms for ergativity yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are creativity, negativity and ergatively.
(n) :
(linguistics) The property of a grammar's (or, by extension, a language's) being ergative; the attribute of possessing a grammatical pattern such that the object of a transitive verb is treated the same way as the subject of an intransitive one, while the subject of the transitive verb is treated differently.
(n) :
(linguistics) The property of a grammar's (or, by extension, a language's) being ergative; the attribute of possessing a grammatical pattern such that the object of a transitive verb is treated the same way as the subject of an intransitive one, while the subject of the transitive verb is treated differently.