Tense, but otherwise flawless (7)
I believe the answer is:
perfect
This clue could be a double definition.
'tense' is the first definition.
(I know that perfect is a type of tense)
'otherwise flawless' is the second definition.
'perfect' can be an answer for 'flawless' (similar in meaning). I'm not sure about the 'otherwise' bit.
'but' is the link.
Can you help me to learn more?
(Other definitions for perfect that I've seen before include "Without blemish" , "Polish" , "Past tense; ideal" , "Mature" , "Exemplary" .)