Mid 19th century; earliest use found in Common School Journal (Boston). From rummy + -ness late 19th century; earliest use found in Erma's Engagement. From rummy + -ness.
Definition of rumminess in US English:
rumminess
nounˈrʌmɪnɪs
The quality of being rummy; the flavour of rum.
nounˈrʌmɪnɪs
The quality of being rummy.
Origin
Mid 19th century; earliest use found in Common School Journal (Boston). From rummy + -ness<br>late 19th century; earliest use found in Erma's Engagement. From rummy + -ness.