Gloss over guides travelling around one school (8)
I believe the answer is:
disguise
'gloss over' is the definition.
(thesaurus)
'guides travelling around one school' is the wordplay.
'travelling' indicates an anagram.
'around' indicates putting letters inside.
'one' becomes 'i' (Roman numeral).
'school' becomes 's'.
'guides' with letters rearranged gives 'dguise'.
'i'+'s'='is'
'dguise' placed around 'is' is 'DISGUISE'.
(Other definitions for disguise that I've seen before include "Alter appearance to conceal identity" , "front" , "act of deception" , "Cover" , "Altered appearance" .)