Irrelevant is an adjective which means something which is not significant or unimportant.
1. The questions asked were irrelevant to our syllabus.
2. The arguments made by the lawyer were irrelevant to the case,
Irreverent is an adjective used to define a person who doesn’t respect things, which are generally taken seriously.
1. Criminal minds are known for irreverence for the laws.
2. The news report was irreverent towards the Prime Minister