Show up live, making comeback to stop dip (6)
I believe the answer is:
debunk
'show up' is the definition.
(thesaurus)
'live making comeback to stop dip' is the wordplay.
'live' becomes 'be' ('be' can be a synonym of 'live').
'making comeback' is a reversal indicator.
'to stop' means one lot of letters goes inside another.
'dip' becomes 'dunk' ('dunk' can be a synonym of 'dip').
'be' backwards is 'eb'.
'eb' going inside 'dunk' is 'DEBUNK'.
(Other definitions for debunk that I've seen before include "Show to be false or unjustified" , "Reveal as false, show up" , "Disprove" , "Expose pretensions of" , "Expose false claims" .)