What does "never mind" really mean?
I am trying to find out the answer for it. I have been hearing that for years, but I don't use it myself because I do NOT know the true meaning.
It means do not think about (something) and is used in a variety of contexts:
You may find even more uses in the Oxford Advanced Learner's Dictionary. Phrases of this sort are usually listed in good dictionaries, after the definitions of the headword.
I'd use it sometimes when trying to talk to someone but it gets so frustrating I give up. For instance:
I might say "The sky is blue."
They might say "Not really. It only appears blue because ...."
I'd reply "Never mind"
To me, it usually means forget about it or don't worry about it.