Entry 1 sense Webster, 1913 Nonsensical /nän-sĕn'-sĭk-əl/ · Non·sen·si·cal · IPA /nɑnsˈɛnsɪkəl/ 01 a. Without sense; unmeaning; absurd; foolish; irrational; preposterous. 1. Without sense; unmeaning; absurd; foolish; irrational; preposterous.