a tan (= brown skin colour caused by the sun) that someone has all the time, especially one that does not come from being in the sun but from a beauty product, a sunlamp, etc.

He tries to divert attention from his receding hairline with a permatan that surely comes from a lamp or a bottle. 他试图用终年不褪的古铜色来转移人们对他发际线后退的注意，这种终年不褪的古铜色肯定来自于仿日晒灯或颜料瓶子。