Train from Waterloo heading North, crossing West End (5)
I believe the answer is:
tutor
'train' is the definition.
(thesaurus)
'waterloo heading north crossing west end' is the wordplay.
'waterloo' becomes 'rout' (I've seen this in other clues).
'heading north' says the letters should be written backwards.
'crossing' means one lot of letters goes inside another.
'end' says to take the final letters.
The final letter of 'west' is 't'.
'rout' written backwards gives 'tuor'.
'tuor' going around 't' is 'TUTOR'.
'from' acts as a link.
(Other definitions for tutor that I've seen before include "college teacher" , "Private educator" , "Master" , "train" , "Guardian" .)