Shirabe
机上 の 空論
English jmdict
1
expressions (phrasesnoun (common) (futsuumeishi) armchair theory;impracticable plan;unworkable idea
What you are saying is nothing but building a castle in the air.
Other forms
Noun Noun
English jmdict
1
noun (common) (futsuumeishi)nouns which may take the genitive case particle 'no' abstract or impracticable theory