Adverbial has 2 senses

• offhandedly(r = adv.all) offhand, offhanded - without previous thought or preparation; "couldn't give the figures offhand"; "she had made these remarks offhandedly"; "we decided offhand to go to Canada"
• offhandedly(r = adv.all) offhand, offhanded - in a casually inconsiderate manner; "replied offhand, his mind a million miles away"; "she threw him over offhandedly without even a Dear-John letter"