DNF = Did Not Find
A simple statement of fact. No details.
It doesn't say we looked for 30 seconds; It doesn't say we looked for 30 minutes.
It doesn't say we knew the cache was still there; It doesn't say that we thought the cache was missing.
It doesn't say any of the things that people have posted that they assume it means, other than that we Did Not Find the cache.
The DETAILS are in the logs.
I've posted a DNF because there were too many muggles near ground zero to safely expose the cache. Why a DNF? Because we Did Not Find the cache. The details in the log could alert other cachers that they may want to choose thier time to look for this one carefully.
This past weekend we were caught looking for a cache by someone who knew where it was. He even told us we were close before he left. Even with his clues, we couldn't find it. Logged the DNF. Not because we thought it might be missing, we knew it wasn't, but because we Did Not Find it.
We've recently logged DNF's on a couple of micro's in the woods. One was last logged over eight months ago, the other even longer ago than that. Both had occasional finds before that. Has nobody actually looked in all that time? Or have they just not logged the DNF's? We'll never know. If I were the CO, I'd want to know.
We even hold the only DNF on a cache that has had 118 successful finds. We logged the DNF, because we Did Not Find the cache. The details let other cachers know that sometimes you don't find them, for whatever reason, and that's OK.