From Longman Dictionary of Contemporary Englishperk up phrasal verb informal1 HAPPYto become more cheerful, active, and interested in what is happening around you, or to make someone feel this way She seemed kind of tired, but she perked up when Helen came over.perk somebody ↔ up There’s no doubt coffee perks you up.2 SMART/WELL-DRESSEDTIDYto become more active, more interesting, more attractive etc, or to make something do thisperk something ↔ up A little chili will perk up the sauce. → perk→ See Verb table
Examples from the Corpus
perk up• She wasn't feeling too good yesterday but she perked up in the evening.• Jessica always perks up when Richard comes over. 