1. Without previous thought or preparation
   "she had made these remarks offhandedly"
   - offhand, offhanded 
2. In a casually inconsiderate manner
   "she threw him over offhandedly without even a Dear-John letter"
   - offhand, offhanded

See also: offhanded

• in her right mind
• in hiding
• in high spirits
• in his own right
• in his right mind
• in its own right
• in kind
• in large quantities
• in league
• in lieu
• in line
• in loco parentis
• in love
• in low spirits
• in media res
• in medias res
• in memoriam
• in name
• in name only
• in no time
• in on
• in one case
• in one ear
• in one's birthday suit
• in one's own right