飘飘然 is a state word (状态词) that literally means 'floating/fluttering lightly'. Figuratively it describes a feeling of smugness, complacency, or euphoria — often when someone becomes self-satisfied after minor success, or feels light-headed with excitement. It carries a slightly negative connotation when used for smugness, but can be neutral or positive when describing genuine exhilaration (e.g., from love or achievement). The word is typically used as a predicate or adverbial complement.