Words: Chimerical

chimerical [ki-mer-i-kuhl, -meer-, kahy-]
–adjective

1. unreal; imaginary; visionary: a chimerical terrestrial paradise.
2. wildly fanciful; highly unrealistic: a chimerical plan.

Also, chimeric.

Origin:
1630–40; chimer(a) + -ical

Related forms:
chimerically, adverb

Synonyms:
1. illusory, fantastic.

Antonyms:
1. real.