IPA: /ɪmˌpræktɪˈkælɪti/
KK: /ɪmˌpræktɪˈkælɪti/
The quality or state of not being practical or useful in a real situation.
The impracticality of the plan made it difficult to implement.
Impracticality is formed from "im-" (meaning not), "practical" (from Latin "practicus", meaning capable of being done or useful), and "-ity" (meaning the state or condition of). The word refers to the state of being not practical or useful.
Think of 'not' ('im-') being combined with 'capable of being done' ('practicus') to remember that 'impracticality' means the state of being not practical.