Show reluctance (5)
'show reluctance' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for demur that I've seen before include "Take exception (to)" , "Hesitation" , "Raise mild objection" , "Dissent, object" , "Protest or disagree mildly" .)
(Other definitions for drag ones feet that I've seen before include "Hang back" , "Be deliberately slow to act" , "Slug" , "Act with reluctance" , "Be reluctant" .)