This is the 16866th most frequent Russian word.
совершенные
"Совершенные" means "perfect" or "completed" in English.
Here, 'соверше́нные' is used as an adjective describing the quality of the paintings, meaning 'perfect' or 'ideal'.
Эти соверше́нные картины восхищают всех.
These perfect paintings amaze everyone.
In this sentence, 'соверше́нные' describes the ballerina's movements and emphasizes their faultlessness or ideal quality.
Движения балерины были совершенно соверше́нные.
The ballerina's movements were absolutely perfect.
Here, 'соверше́нные' describes 'samples' of modern art, indicating their exceptional quality or perfection.