IPA: /ˈsiːm.lɪ.nəs/
KK: /ˈsimlɪnəs/
The quality of being proper, appropriate, or suitable in behavior or appearance.
Her seemliness at the formal event impressed everyone.
Seemliness is formed from "seem" (from Old English "seman", meaning to appear or to be fitting) and "-liness" (a suffix indicating a quality or state). The word refers to the quality of being appropriate or fitting in appearance or behavior.
Think of the word 'seem' which relates to how things appear, combined with '-liness' that indicates a quality. This helps you remember that 'seemliness' is about the quality of appearing appropriate or fitting.