slip up on
slip up on (someone or something)
1. To approach someone or something in a quick, sneaky, and furtive manner so as to reach them or it without being noticed. Someone managed to slip up on Sneaky Pete, which I thought was all but impossible! The spy slipped up on the guard tower and cut the power to the lights and security cameras.
2. To happen to or unfold before someone in a very quick, imperceptible manner. Old age has slipped up on me. Where have all the years gone? It feels like the gentrification of this town has been slipping up on those of us who've lived here our whole lives.
3. To make a foolish blunder or mistake in, about, or regarding something. I think I slipped up on the address when I was shipping your package. Wow, it looks like the accountants must have really slipped up on the tax return.
slip up on (someone, something, or an animal)
to sneak up on someone, something, or an animal quietly. I slipped up on Harry and scared him to death. The cat slipped up on a mouse and grabbed it.
slip up on something
to make an error in something. I guess I slipped up on that last job. Fred slipped upon compiling that list—there are a lot of names missing.