Dull sort of leap (4)
I believe the answer is:
pale
'dull' is the definition.
(thesaurus)
'sort of leap' is the wordplay.
'sort of' indicates an anagram.
'leap' is an anagram of 'PALE'.
(Other definitions for pale that I've seen before include "Having less colour than normal" , "Not bright - limit" , "Stake, lacking colour" , "Very light coloured" , "Light-coloured" .)