Not based on fact; unreal. Synonyms:fanciful, imaginary."A small child's imaginary friends" , "To create a notional world for oneself"
2.
Not based on fact or investigation. Synonym:speculative."Speculative knowledge"
3.
Indulging in or influenced by fancy. Synonym:fanciful."All the notional vagaries of childhood"
4.
Being of the nature of a notion or concept. Synonyms:conceptional, ideational."To improve notional comprehension" , "A notional response to the question"
