Wandering, initially rambling content of Lincoln bombast (8)
I believe the answer is:
aberrant
'wandering' is the definition.
(I've seen this before)
'initially rambling content of lincoln bombast' is the wordplay.
'initially rambling' becomes 'abe' (I can't justify this - if you can you should believe this answer much more).
'content of' indicates the central letters.
'lincoln' becomes 'formerpresident' (I've seen this in another clue).
'bombast' becomes 'rant' (synonyms).
The middle letter of 'formerpresident' is 'r'.
'abe'+'r'+'rant'='ABERRANT'
Can you help me to learn more?
(Other definitions for aberrant that I've seen before include "Departing from type" , "Departing from the norm" , "Wandering, straying" , "Deviating from what is accepted" , "Divergent from the normal" .)