to drift, float, careless, reckless
泛 centers on floating or drifting without fixed direction, which extends naturally to careless or reckless behavior—acting as if adrift without steady control.
泛 combines 氵 (water) with 乏, which likely contributes the sound and the idea of lacking or being insufficient, together suggesting floating or drifting on water without a firm hold.
Water 氵 plus 乏 (lacking) gives the image of something lacking a fixed place on the water, just drifting along. That aimless drifting is also like a careless, reckless attitude.
For ハン, imagine a hand (ハン sounds like 'hand') carelessly drifting through water, not holding onto anything: hand -> ハン, and the hand floats recklessly.