IPA: /ɪˈnæptɪtjuːd/
KK: /ɪˈnæptɪtud/
A lack of skill or ability to do something well.
His inaptitude for mathematics was evident in his poor grades.
Inaptitude is formed from "in-" (meaning not) and "aptitudo" (from Latin "aptus", meaning fit or suitable, with the suffix "-tudo" indicating a state or condition). The word describes a state of being not fit or suitable for a particular task or role.
Think of 'not' ('in-') being combined with 'fit' ('aptus') to remember that inaptitude means a lack of fitness or suitability for something.