non-thematic
/ˌnɒnθiːˈmatɪk/ /ˌnɒnθɪˈmatɪk/adjective
1= athematic.
2Not conveying any further information; forming part of the rheme.
3Having no theme; (Music ) = athematic.
Origin
1930s; earliest use found in Edgar Sturtevant (1875–1952). From non- + thematic.