Irregardless is a real word in the sense that it has been used for a long time and is recorded in major dictionaries. But those dictionaries usually label it nonstandard, which means many readers and editors still consider it incorrect or careless.
Its meaning is the same as regardless. For example, Irregardless of the weather, we went outside means the same thing as Regardless of the weather, we went outside.
So why do people object to it? Many speakers hear ir and less together and assume the word is illogical. Even so, English contains many words that developed through actual use rather than neat logic.
For practical writing, the best advice is simple:
- Use regardless in school, work, and formal writing.
- Recognize irregardless if you hear or read it.
- Know that some people use it naturally, but many readers will judge it negatively.
If your goal is clear, careful prose, regardless is usually the better choice.
