IPA: //ˈpræktɪkəl.nəs//
KK: /ˈpræktɪkəlnəs/
The quality of being useful and effective in real situations, rather than just in theory.
Her practicalness in solving problems made her a valuable team member.
Practicalness → It is formed from "practical" (from Latin *practicus*, meaning effective or suitable for action) and the suffix "-ness" (meaning the state or quality of). The word "practicalness" refers to the quality of being practical or suitable for real-world use.
Think of the word 'practical' which means effective or suitable for action, and remember that 'practicalness' describes the quality of being practical.