Fake journey back in bus (5)
I believe the answer is:
bogus
'fake' is the definition.
(I know that fake can be written as bogus)
'journey back in bus' is the wordplay.
'journey' becomes 'go' (I've seen this in other clues).
'back' is a reversal indicator.
'in' means one lot of letters goes inside another.
'go' backwards is 'og'.
'og' going within 'bus' is 'BOGUS'.
(Other definitions for bogus that I've seen before include "Not genuine, sham" , "taking one for a ride?" , "Sham, phoney" , "Phoney, not genuine" , "Fake, sham" .)