do (someone) a favor
idiom
variants:
or do a favor for (someone)
Definition of do (someone) a favor
: to do a kind and helpful act for (someone)
You can do your uncle a favor by giving him a ride. Do me a favor, please, and help me move this.
—the phrase Do me a favor is sometimes used in an ironic way when a person wants someone to do something that he or she should do anyway Do me a favor and get home on time for once.