Here's what rhymes with impracticable.

Consider these alternatives

impractical / practical unfeasible / feasible inadvisable / advisable infeasible / feasible illogical / logical uneconomic / economic unviable / double counterproductive / productive unsuited / routed undignified / side unwise / size inexpedient / expedient unpractical / practical superfluous / thus unappealing / feeling implausible / plausible unmanageable / manageable maddening / happening futile / pupil