adjective
impertinent
im-PURT-nunt/ɪmˈpɜːrtnənt/
Rude or disrespectfully bold.
The impertinent listener interrupts the speaker with a smirk and dismissive gesture.

Etymology
“Not relating to the matter” shifted to “inappropriate to the situation,” then to rude boldness through the idea of meddling beyond one's proper sphere.
In context
to his credit, Steve apologized for his impertinent questions in a later post.
More examples
- The teacher asks him to apologize for his impertinent remark.
- I hope you won't think me impertinent for asking your age.
- Her impertinent reply earns a stern look from the judge.
Forms
impertinent
impertinence noun — Rude or disrespectfully bold behavior.
impertinently adverb — In a rude or disrespectfully bold manner.