Open English Wordnet
Adverbs
(r)offhand, offhanded, offhandedlywithout previous thought or preparation“couldn't give the figures offhand”, “we decided offhand to go to Canada”, “she had made these remarks offhandedly”
(r)offhand, offhanded, offhandedlyin a casually inconsiderate manner“replied offhand, his mind a million miles away”, “she threw him over offhandedly without even a Dear-John letter”