casually thoughtless or inconsiderate; "an offhand manner"; "she treated most men with offhand contempt"
in a casually inconsiderate manner; "replied offhand, his mind a million miles away"; "she threw him over offhandedly without even a Dear-John letter"
without previous thought or preparation; "couldn't give the figures offhand"; "we decided offhand to go to Canada"; "she had made these remarks offhandedly"
without apparent forethought or prompting or planning; "an unplanned economy"; "accepts an unplanned order"; "an unplanned pregnancy"; "unplanned remarks"