smartened up; smartening up; smartens up
Definition of smarten up
1 US : to become more intelligent or aware : to become smarter He'd better smarten up or he'll get fired.
2 US : to make (someone or something) smarter or more aware Someone needs to smarten him up before he gets in trouble.
3 : to make (someone or something) neat and attractive They smartened themselves up for the party. They smartened up the room for the party.
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