Not sure about the context of the sibling posts (FU money might mean something different in SV) but within the FIRE community (UK atleast) FU money tends to ref

Not sure about the context of the sibling posts (FU money might mean something different in SV) but within the FIRE community (UK atleast) FU money tends to refer to less money than full FIRE. FIRE means you never have to work again (normally 25x annual spending), FU money means you can quit in extreme circumstances and have enough money to tide over any job search (min of 6-12 months spending).