Boiling apparatus not bubbling yet (5)
I believe the answer is:
still
'yet' is the definition.
(synonyms)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for still that I've seen before include "not bubbly" , "not like champagne" , "Yet; not moving" , "'Quiet!'" , "Motionless, inactive" .)