Eccentric, tedious man in bank (12)
I believe the answer is:
mountainside
'bank' is the definition.
The answer and definition can be both natural objects as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'eccentric tedious man in' is the wordplay.
'eccentric' indicates anagramming the letters.
'tedious'+'man'+'in'='tediousmanin'
'tediousmanin' anagrammed gives 'MOUNTAINSIDE'.
Can you help me to learn more?
(Other definitions for mountainside that I've seen before include "where many adventurous explorers go?" , "Incline" , "Big hill slope" , "It isn't flat" , "One's inclined" .)