Dawdle; insulate (3)
I believe the answer is:
lag
I believe this clue is a double definition.
'dawdle' is the first definition.
(synonyms)
'insulate' is the second definition.
(I've seen this before)
(Other definitions for lag that I've seen before include "trail" , "Go too slow, fail to keep up" , "Wrap to protect from frost" , "An old one is a convict" , "Insulate (pipes)" .)