Example : A certain irreverent gaiety and ease of manner.

Synonyms : irreverent, pert, saucy

Example : An issue extraneous to the debate.
The price was immaterial.
Mentioned several impertinent facts before finally coming to the point.

Synonyms : extraneous, immaterial, orthogonal

Example : Don't be fresh with me.
Impertinent of a child to lecture a grownup.
An impudent boy given to insulting strangers.
Don't get wise with me!.

Synonyms : fresh, impudent, overbold, sassy, saucy, smart, wise