IPA: /ˈsuːtəblnəs/
KK: /ˈsutəblnəs/
The quality or state of being appropriate or fitting for a particular purpose or situation.
The suitableness of the dress for the occasion impressed everyone at the party.
Suitableness → It is formed from "suit" (from Old French *suiter*, meaning to follow or be appropriate) and "-able" (meaning capable of) and "-ness" (meaning the state of). The word "suitableness" refers to the state of being appropriate or fitting for a particular purpose.
Think of something that is 'appropriate' ('suit') and 'capable of' ('-able') being that way, plus the 'state of' ('-ness') — that's why suitableness means the state of being appropriate.