IPA: /ɪmˈpɜːrtɪnənsi/
KK: /ɪmˈpɜːrtɪnənsi/
The quality of being rude or disrespectful, especially in a way that is not appropriate or relevant to the situation.
His impertinency during the meeting upset many of his colleagues.
Impertinency is formed from "im-" (meaning not) and "pertinere" (meaning to pertain or relate). The word describes a quality of not being relevant or appropriate in a given context.
Think of 'not' ('im-') relating to something ('pertinere') — that's why impertinency means something that is not relevant or appropriate.