chimerical       
adjective  formal uk/kaɪˈmer.ɪ.kəl/ us/kaɪˈmer.ɪ.kəl/
 妄想的;荒诞不经的
relating to a hope or dream that is extremely unlikely ever to come true
  His self-image as a writer seems chimerical. 他作为作家的自我形象似乎是臆想出来的。 
 As if the real world weren't scary enough, chimerical threats are everywhere. 好像现实世界还不够可怕似的,妄想虚构的威胁也无处不在。 
 See: chimera
 - More examples
 - The possibility of success was chimerical.
 - The weapons capability they claim is more chimerical than it is real.
 - the chimerical dream of progress