During tango performance is unimpaired (6)
I believe the answer is:
intact
'unimpaired' is the definition.
('intact' can be similar in meaning to 'unimpaired')
'during tango performance' is the wordplay.
'during' becomes 'in' (I've seen this in other clues).
'tango' becomes 't' (phonetic alphabet: alpha, bravo, charlie etc.).
'performance' becomes 'act' (act is a kind of performance).
'in'+'t'+'act'='INTACT'
'is' is the link.
(Other definitions for intact that I've seen before include "Unbroken and unimpaired" , "Entire, undamaged" , "Entire, untouched" , "Whole - unbroken" , "Entire and whole" .)