A person who refuses to do favors or acts in an unhelpful manner.
From dis- (prefix meaning 'opposite of') + obliger (one who obliges), derived from Old French obliger meaning 'to bind or constrain.' The prefix dis- negates the helpful quality of an obliger.
This is a fascinating relic word from the 17th-18th centuries—it's the kind of specialized vocabulary that emerged when English was rapidly expanding and writers loved creating 'dis-' versions of words. It reveals how people valued social courtesy so much they had a specific word for someone who violated it.
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