Hi, my 1.6L 4-cylinder Civic often makes a "clicking" noise, especially
when under load in too high a gear. Sometimes even at the "correct"
gear, when accelerating.

Is this pinging, pinking, tappet noise, detonation, spark knock, etc?
I've searched the posts, but I'm now more confused. Some people say
"pinging" is the same as tappet noise, which is harmless, while some
say pinging = detonation, which is bad.

So which is it, really, and what could be causing it on my engine?

Thanks!