Jazzy solo with echo not tight (5)
I believe the answer is:
loose
'not tight' is the definition.
('loose' is the opposite to 'tight')
'jazzy solo with echo' is the wordplay.
'jazzy' is an anagram indicator.
'with' is a charade indicator (letters next to each other).
'echo' becomes 'e' (phonetic alphabet: alpha, bravo, charlie etc.).
'solo' anagrammed gives 'loos'.
'loos'+'e'='LOOSE'
(Other definitions for loose that I've seen before include "Relaxed; not tethered" , "Free or immoral" , "Lax - inaccurate - unbound" , "Untie(d)" , "Imprecise" .)