Wavered when reflated badly (8)
I believe the answer is:
faltered
'wavered' is the definition.
('falter' can be a synonym of 'waver')
'reflated badly' is the wordplay.
'badly' is an anagram indicator (letters in the wrong order).
'reflated' anagrammed gives 'FALTERED'.
'when' acts as a link.
(Other definitions for faltered that I've seen before include "Hesitated, moved unsteadily" , "was hesitant" , "Failed" .)