Tense, but otherwise flawless (7)
I believe the answer is:
perfect
This clue might 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 unsure of 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" .)