/smahr"tn/ , v.t.
1. to make more trim or spruce; improve in appearance (usually fol. by up ): Try to smarten up your outfit.
2. to make brisker, as a pace.
3. to sharpen the judgment or broaden the experience of; educate (usually fol. by up ): Someone has to smarten him up about dealing with people.
4. smarten up ,
a. to groom oneself: to smarten up before dinner.
b. to become aware of one's mistakes, shortcomings, etc., and make efforts to correct them: If you don't smarten up, you're going to be out of a job.
[ 1805-15; SMART + -EN 1 ]