Noun
disregard for other's feelings
heedless disregard for the consequences of one's actions
Source: en.wiktionary.orgIn the sex war, thoughtlessness is the weapon of the male, vindictiveness of the female. Cyril Connolly
Men have made an idol of luck as an excuse for their own thoughtlessness. Luck seldom measures swords with wisdom. Most things in life quick wit and sharp vision can set right. Democritus
The thinking man must ... oppose all cruel customs no matter how deeply rooted in tradition and surrounded by a halo. True manhood is too precious a spiritual good for us to surrender any part of it to thoughtlessness. Albert Schweitzer
Government is an evil; it is only the thoughtlessness and vices of men that make it a necessary evil. When all men are good and wise, government will of itself decay. Percy Bysshe Shelley
People who don't see their nature and imagine they can practice thoughtlessness all the time are lairs and fools. Bodhidharma
Very little of the great cruelty shown by men can really be attributed to cruel instinct. Most of it comes from thoughtlessness or inherited habit. Extract from 'Memories of childhood and youth.' Albert Schweitzer