IPA: /ˌæp.tɪˈtjuː.dɪ.nəl/
KK: /æpˈtɪtʃʊdɪnəl/
Relating to a person's natural ability or talent for something.
Her aptitudinal skills in mathematics helped her excel in the competition.
Aptitudinal → It is formed from "apt" (from Latin "aptus", meaning suitable or fit) and "-itudinal" (derived from "-itude", a suffix indicating a state or condition). The word "aptitudinal" refers to the state or condition of being suitable or fit for a particular purpose or task.
Think of 'apt' meaning suitable or fit, and remember that 'aptitudinal' describes the state of being suitable for something.