Replacing tip on cue that's dull (8)
I believe the answer is:
unpoetic
'dull' is the definition.
(thesaurus)
'replacing tip on cue' is the wordplay.
'replacing' is an anagram indicator (placing again).
'tip'+'on'+'cue'='tiponcue'
'tiponcue' with letters rearranged gives 'UNPOETIC'.
'that's' acts as a link.
(Other definitions for unpoetic that I've seen before include "Not in the style of verse" , "prosaic" .)