Shrub no dealer can possibly supply (8)
I believe the answer is:
oleander
'supply' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'shrub no dealer can' is the wordplay.
'shrub' becomes 'o' (I can't explain this - if you can you should give a lot more credence to this answer).
'no' becomes 'n' (common abbreviation y/n).
'can' indicates an anagram (I've seen 'canned' mean this (canned can mean drunk)).
'n'+'dealer'='ndealer'
'ndealer' anagrammed gives 'leander'.
'o'+'leander'='OLEANDER'
'possibly' acts as a link.
Can you help me to learn more?
(Other definitions for oleander that I've seen before include "Mediterranean shrub" , "bloomer" , "Poisonous shrub, also called rosebay" , "Poisonous evergreen shrub with white, pink or red flowers" , "Flowering shrub from olden era, oddly" .)