Imposing for a while (6)
I believe the answer is:
august
'imposing' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for august that I've seen before include "It follows 8" , "Month named after emperor of Rome" , "a period for taking holidays?" , "Eighth month" , "Roman emperor's month" .)