Travel round something sticky (3)
I believe the answer is:
goo
'something sticky' is the definition.
'travel round' is the wordplay.
'travel' becomes 'go' (synonyms).
'round' becomes 'o' (o is a circular letter).
'go'+'o'='GOO'
(Other definitions for goo that I've seen before include "mud, for example" , "Sticky matter" , "Substance that's viscous" , "Sticky and slimy stuff" , "Sentimentality (sl.)" .)