Insect set free by misguided set (6)
I believe the answer is:
tsetse
'insect' is the definition.
(tsetse is a kind of insect)
'set free by misguided set' is the wordplay.
'free' is an anagram indicator.
'by' says to put letters next to each other.
'misguided' is an anagram indicator (I've seen this in other clues).
'set' anagrammed gives 'tse'.
'set' with letters rearranged gives 'tse'.
'tse'+'tse'='TSETSE'
(Other definitions for tsetse that I've seen before include "carrier of disease" , "bloodsucker" , "Bloodsucking African fly" , "Disease-carrying fly" , "cause of sleepiness?" .)