What it means
Means nothing at all, same vibe as sweet FA. It’s the polite-ish way of saying you did or got basically zero, without dropping the rude version. Used when you’re admitting you’ve been useless, or when you’re moaning that something delivered absolutely nothing. Often said with a shrug and a bit of cheek.
Usage examples
"What’d you do on your day off? Naff all, mate, stayed in me trackies, smashed a bag of crisps, and watched Bargain Hunt."
"I revised for a week and the exam asked naff all about any of it, typical."
"There's naff all in the fridge except half a lemon and a yoghurt from last month."
"Asked him what he brought to the group project and it was naff all apart from excuses."
"We got to the shop five minutes before closing and there was naff all left but a sad sandwich."