Like the rocky road to the centre of Le Havre! (4)
I believe the answer is:
hard
'like' is the definition.
Both the answer and definition are adjectives. Perhaps there's an association between them I don't understand?
'rocky road to the centre of le havre' is the wordplay.
I cannot quite see how this works, but
'road' could be 'rd' (abbreviation) and 'rd' is found in the answer.
The remaining letters 'ha' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'the' is the link.
Can you help me to learn more?
(Other definitions for hard that I've seen before include "Novel featuring Mr Gradgrind" , "Newspaper's sure" , "Emergency lane" , "Difficult; severe" , "Difficult; rigid" .)