1. being of the nature of a notion or concept - a plan abstract and conceptional - to improve notional comprehension - a notional response to the question • Syn: conceptional, ideational • Similar to: abstract • Derivationally related forms: notion, ideation (for: ideational), conception (for: conceptional) 2. indulging in or influenced by fancy - a fanciful mind - all the notional vagaries of childhood • Syn: fanciful • Similar to: creative, originative 3. not based on fact; unreal - "the falsehood about some fanciful secret treaties"- F.D.Roosevelt - a small child's imaginary friends - to create a notional world for oneself • Syn: fanciful, imaginary • Similar to: unreal 4. not based on fact or investigation - a notional figure of cost helps in determining production costs - speculative knowledge • Syn: speculative • Similar to: theoretical, theoretic • Derivationally related forms: speculativeness (for: speculative), speculate (for: speculative)