What does forgiving actually mean in golf clubs?

I didn't mean left to right dispersion (although this was also tighter in MC's test), I was referring to front to back dispersion. There's quite a lot of stuff out there that I've watched which suggests that blades have tighter front to back dispersion, i.e. they don't lose as much distance as cavity backs.

I started playing with blades and when I switched to cavity backs I found the game easier, but I don't know if that was a mental thing and/or coincided with a general improvement in my swing because I was practising like mad at the time. You'd need to play a few rounds with each to see if there is a real difference for each person, so I wondered if there is actually an accepted 'definition'?

If it is - as I thought it was - that blades are meant to lose more distance than cavity backs for off-centred strikes, how come so many YouTubers are suggesting the opposite?