IPA: /ʌˈnæptnəs/
KK: /ʌˈnæptnəs/
The quality of being unsuitable or not appropriate for a particular situation or purpose.
His unaptness for the role was evident during the interview.
Unaptness → It is formed from "un-" (meaning not) and "apt" (from Latin "aptus", meaning suitable or fit) and the suffix "-ness" (meaning the state of being). The word "unaptness" refers to the state of not being suitable or fit for a particular purpose.
Think of 'not' ('un-') being combined with 'suitable' ('apt') to remember that 'unaptness' means the state of not being suitable.