The quality or state of being choosable; the characteristic of being capable of being chosen.
From 'choosable' plus the suffix '-ness,' which converts adjectives to abstract nouns referring to the quality described.
English loves stacking suffixes to create increasingly abstract concepts—'choose' becomes 'choosable' (an adjective) which becomes 'choosableness' (the abstract quality itself), allowing us to think about thought processes philosophically!
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