Rare problem - has doctor left hiker? (7)
I believe the answer is:
rambler
'hiker?' is the definition.
(I've seen this before)
'rare problem has doctor left' is the wordplay.
I cannot quite understand how this works, but
'rare' could be 'r' (listed by Oxford Dictionary of Abbreviations) and 'r' is present in the answer.
'doctor' could be 'mb' (Bachelor of Medicine, Medicinae Baccalaureus) and 'mb' is found in the answer.
'left' could be 'al' (I've seen this in other clues) and 'al' is found in the remaining letters.
The remaining letters 'er' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for rambler that I've seen before include "one going on and on?" , "who's not heading for the point" , "Kind of climbing rose" , "One who goes on country walks" , "Countryside walker" .)