Creep (along) (4)
I believe the answer is:
inch
'creep along' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for inch that I've seen before include "2.54cm" , "A very little" , "One 63,360th of a mile" , "25.4 millimetres" , "One twelfth of a foot" .)