Go furtively (5)
(Other definitions for creep that I've seen before include "Move slowly with body close to ground" , "Slink" , "Fawn" , "Steal" , "Crawl; skulk" .)
'go furtively' is the definition.
(I've seen this in another clue)
This is all the clue.
(Another definition for slink that I've seen is " Hide".)