having no bearing on or connection with the subject at issue
"an irrelevant comment"
"irrelevant allegations"
Not related, not applicable, unimportant, not connected.
"The discussion about budget cuts became irrelevant when we realized the project had already been cancelled."
In plain English: Something irrelevant has nothing to do with what is being discussed and does not matter at all.
"The weather forecast was completely irrelevant to our indoor game plan since we were staying inside anyway."
Usage: Use irrelevant to describe information that has no bearing on the matter at hand or is completely unrelated to the topic being discussed. This word applies whether something lacks importance due to its disconnect from the current situation or simply because it does not fit within the relevant context.
The word irrelevant comes from combining the prefix ir- with relevant to mean not applicable or connected. It entered English as a direct negation of its related term, keeping the original sense of being unrelated.