There's nuance worth teasing apart here.
The only definition I've ever heard is that UBI allows you to lose your job and still be able to pay for the basic necessities (food, water, shelter, transportation, etc.). Anything less misses the whole point.
However, just the basic necessities would make for a pretty dull and repetitive life, which most people hate. And so the idea (as I understood it) is that it's not supposed to go beyond that, so your incentive would still be to keep your job if you at all can, not quit it.
