(Archaic definition) A sudden desire or change of mind, especially one that is unusual or unexplained.
‘He opened the door on a whim, expecting nothing, but instead, he was faced with four sets of eyes.’
‘She did it on a whim when the opportunity presented itself, and she died four days later.’
‘Apparently on a whim, Wonka suddenly decides to reopen his doors to five children.’
‘come on, you poltroons!’
‘It encourages people to mail or email white feathers to Jonah to remind him that he is a lily-livered poltroon.’
‘I knew what they were both thinking, for I was thinking it myself; he was a yellowed-belly poltroon.’