Dissatisfaction seen in Nubia at regular intervals (5)
I believe the answer is:
ennui
'dissatisfaction' is the definition.
(ennui is a kind of dissatisfaction)
'seen in nubia at regular intervals' is the wordplay.
'at regular intervals' means one should take alternating letters.
'seen'+'in'+'nubia'='seeninnubia'
The alternate letters of 'seeninnubia' are 'ENNUI'.
(Other definitions for ennui that I've seen before include "Boredom, dullness" , "World-weariness" , "Boredom, tedium" , "Lower interest rate" , "Weary feeling" .)