Imposing, a state capital (7)

I believe the answer is:

augusta

'state capital' is the definition.
(Augusta is an example)

'imposing a' is the wordplay.
'imposing' becomes 'august' (I've seen this before).
'august'+'a'='AUGUSTA'

(Other definitions for augusta that I've seen before include "US city" , "Girl - state capital" , "Lady Bracknell" , "US state capital - girl's name" , "Algernon's aunt (Importance of Being Earnest)" .)

I've seen this clue in The Telegraph.

Want a hint initially instead of a full solution? Install my app