Hello hkalu78!
Adeniums typically go dormant during the cold season. Either it keeps some leaves, or it may start to get brown leaves and eventually drop all of them so it goes bare, or it may be in bloom but still dormant.
When my Adeniums start to manifest dormancy I start reducing watering to none. Much younger Adeniums may need more. But if it is a matured one with well formed caudex it can go dormant with no water. I just keep mine by our south facing window. It does not go out again till our outdoor overnight temps return to sustained 50F and higher. When the sustained overnight temps it needs is back, it is brought out slowly, in part shade/sun till it acclimates again to outdoor conditions, and once new leaves start to grow, then watering resumes.
Try to get a photo and also feel the caudex. If it is shrunken but staying firm, then it is okay, just in dormancy mode. This plant is happiest with the warmest temps and direct sun of summer, so it is understandably just resting when temps are not to its preference.
