omissibility
/ə(ʊ)ˌmɪsɪˈbɪlɪti/noun
The quality or state of being omissible; (Linguistics ) the property of being omissible without impairing the syntactic acceptability of a sentence or clause.
Origin
1950s; earliest use found in Lingua: international review of general linguistics. From omissible + -ity: see -bility.