When is a wiretap not a wiretap?

But now the Republicans have informed me that when Donald Trump accused his predecessor, President Obama, of wiretapping him, Trump didn’t intend to be taken literally. 
You see, I’m so stupid that I never knew that “wiretapping” is just a figure of speech. So it was wrong of me to think that Trump (I still refuse to call him “President”) is a liar and a slanderer who should be impeached and kicked out of office.
So what does it really mean to accuse someone of “wiretapping”? How should I know? I’m stupid!
Eric Bahrt