Speak indistinctly and insult (4)
I believe the answer is:
slur
I believe this clue is a double definition.
'speak indistinctly' is the first definition.
(I've seen this in another clue)
'insult' is the second definition.
(I've seen this in another clue)
'and' is the link.
(Other definitions for slur that I've seen before include "Insinuation; indistinct utterance" , "Slight; blur" , "libel" , "Defamation" , "Slight - stain" .)