English to English adjective
1 
Existing only in imagination or fancy; not real; fancied; visionary; ideal.  source: webster1913 adjective satellite
2 
not based on fact; unreal  Example:
• the falsehood about some fanciful secret treaties • a small child's imaginary friends • to create a notional world for oneself
source: wordnet30 noun
3 
(mathematics) a number of the form a+bi where a and b are real numbers and i is the square root of 1  source: wordnet30
4 
An imaginary expression or quantity.  source: webster1913
