To become more lively or cheerful. She began to perk up after hearing the good news.
To raise or lift something, especially the head, in a lively or alert manner. The dog perked its ears at the sound of the doorbell.
To improve or enhance something, often by adding something extra. He decided to perk up the room with some fresh flowers.
To percolate, especially of coffee while it is brewing. The coffee was already perking on the stove when she woke up.