"offhandedly" in the adverb sense
1. offhand, offhanded, offhandedly
without previous thought or preparation
"couldn't give the figures offhand"
"we decided offhand to go to Canada"
"she had made these remarks offhandedly"
2. offhand, offhanded, offhandedly
in a casually inconsiderate manner
"replied offhand, his mind a million miles away"
"she threw him over offhandedly without even a Dear-John letter"
Source: WordNet® (An amazing lexical database of English)
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