Go furtively to steal (5)
I believe the answer is:
sneak
I believe this is a double definition.
'go furtively' is the first definition.
(I've seen this before)
'steal' is the second definition.
(sneaking is a kind of stealing)
'to' is the link.
(Other definitions for sneak that I've seen before include "Move furtively - informer" , "Go furtively and tell tales" , "Go furtively - inform on another child" , "Slink, skulk; tell tales" , "To go stealthily" .)