零花 is a verb meaning 'to spend on small, incidental expenses' — the kind of casual spending you do with pocket money or petty cash. It's often used in the pattern 零花钱 (pocket money / spending money), where 零花 modifies 钱. As a verb, it's less common than the noun form 零花钱, but you'll see it in contexts like 零花掉 ('spend on incidentals').