No walk in the park (4)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
trek
'no walk in the park' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for trek that I've seen before include "Expedition or difficult trip" , "Tramp" , "A long hard march" , "Footslog" , "Slog" .)