Two coexisting senses: classical
风月 = 'wind and moon' = pure natural beauty (think
风花雪月 fēng huā xuě yuè 'wind, flower, snow, moon' — the four classical poetic motifs). But
风月场 fēngyuèchǎng and
风月片 fēngyuèpiàn refer to brothels and softcore films respectively. Same word, opposite registers — context tells you which.
