This is a jukugo word that uses the on'yomi readings of the kanji. You haven't learned this reading for 浮 yet, so here's a mnemonic to help you:
All the vagrants you know are fools (ふ). They just left their homes and now they float around your city for no reason. You ask them why and they shrug. You've never seen a better definition of a fool before in your life!
70% of vagrants do some kind of work and earn a daily cash income.