Move awkwardly in sleep, hiding head (6)
I believe the answer is:
lumber
'move awkwardly' is the definition.
(to lumber is to stumble around)
'sleep hiding head' is the wordplay.
'sleep' becomes 'slumber' (synonyms).
'hiding head' means to remove the first letter.
'slumber' with its initial letter removed is 'LUMBER'.
'in' acts as a link.
(Other definitions for lumber that I've seen before include "Sawn timber" , "Cut timber - useless objects" , "Move heavily; timber" , "Unwanted, stored goods" , "Wood for building - saddle" .)