Here's what rhymes with unanswerable.

Consider these alternatives

imponderable / comparable inane / main illogic / logic abstruse / use truthfulness / usefulness immaterial / material rephrased / based unfathomable / fashionable rephrase / days mystifying / dying unstated / dated impudent / student quibble / little replying / trying exhortation / operation uninitiated / dated touchy / study unimportant / important