A journey without end lacking interest (4)
I believe the answer is:
arid
'lacking interest' is the definition.
(I've seen this in another clue)
'a journey without end' is the wordplay.
I cannot really understand how this works, but
'a' is within the answer.
The remaining letters 'rid' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for arid that I've seen before include "Dry and barren" , "Dry and withered" , "Dry and sere" , "Without water" , "(Of an area) very dry" .)