smarten up
phrasal verb
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.