Synonyms for Impracticality:

n.

inapplicability, idealism, impossibility, unworkability, worthlessness. hopelessness (noun)
impossibility.
impossibility (noun)
unworkability.
inefficiency (noun)
uselessness, impossibility, inapplicability, unworkability, worthlessness.
inutility (noun)
unsuitability, fruitlessness, futility, inadequacy, failure, ineffectiveness, uselessness, good-for-nothingness, Detrimentalness.

Other synonyms:

idealism. uselessness
worthlessness.
Other relevant words:
inapplicability, idealism, impossibility, unworkability, worthlessness.