IPA: /kəˈkeɪbəl.nəs/
KK: /kəˈpeɪbəl.nəs/
The condition of having the ability or qualities to do something.
Her capableness in handling complex tasks impressed her manager.
Capableness is formed from "capable" (from Latin "capabilis", meaning able to hold or contain) and the suffix "-ness" (meaning the state or quality of). The word "capableness" refers to the quality of being capable or able to do something.
Think of 'capable' meaning able, and '-ness' indicating a state. This helps you remember that 'capableness' refers to the state of being able to do something.