Fellow, with current friend, about to get misleading notion (7)
I believe the answer is:
fallacy
'misleading notion' is the definition.
The answer and definition can be both related to thinking as well as being singular nouns.
Maybe there's a link between them I don't understand?
'fellow with current friend about' is the wordplay.
'fellow with' becomes 'f' (I've seen this in other clues).
'current' becomes 'ac' (alternating current).
'friend' becomes 'ally' (synonyms).
'about' indicates putting letters inside.
'ac' placed into 'ally' is 'allacy'.
'f'+'allacy'='FALLACY'
'to get' acts as a link.
Can you help me to learn more?
(Other definitions for fallacy that I've seen before include "A mistake in reasoning" , "False or mistaken belief." , "Illogical argument" , "Wrong but prevalent notion" , "Delusion" .)