IPA: /ˈmɛsɪnəs/
KK: /ˈmɛsɪnəs/
The quality or state of being untidy or disorganized.
The messiness of his room made it hard to find anything.
Messiness → It is formed from "mess" (from Old French *mes*, meaning a portion or a mixture) and "-iness" (meaning the state or quality of). The word "messiness" refers to the state of being messy or disordered.
Think of a 'mixture' ('mess') that is in a 'state' ('-iness') of disorder — that's what messiness means.