Groovy was a human slang word meaning cool, often in an unusual or unexpected way.
A group of strangely dressed people that the First Doctor encountered in London used the word "groovy" upon learning that he was a Time Lord. The First Doctor didn't like this word. (PROSE: Dr. First)
Jess Collins' boyfriend Dave used to say that things were groovy. He thought Egyptian Avenue was groovy. (COMIC: The Highgate Horror)
In Atlantis, Jo Grant said that her dress was groovy. She later said that the appearance of the Time Vortex was groovy. (TV: The Time Monster) During the Eleventh Doctor's funeral, she thought it was groovy that there was something wrong, "just like the old days". (TV: Death of the Doctor)
The Eleventh Doctor thought it was groovy that he was facing not just pirates, but also a demon. (TV: The Curse of the Black Spot)