Acts as guide abroad, they say (8)
I believe the answer is:
oversees
'acts as guide' is the definition.
'abroad they say' is the wordplay.
'abroad' becomes 'overseas' ('overseas' can be a synonym of 'abroad').
'they say' indicates a 'sounds like' (homophone) clue.
'overseas' sounds like 'OVERSEES'.
(Other definitions for oversees that I've seen before include "Supervises" , "Watches" .)