I .
perk up | ˌperk sb ↔ ˈup
( informal ) to become or to make sb become more cheerful or lively, especially after they have been ill / sick or sad
SYN brighten :
He soon perked up when his friends arrived.
II .
perk up | ˌperk sth ↔ ˈup
( informal ) to increase, or to make sth increase in value, etc. :
Share prices had perked up slightly by close of trading.