Lubricate vehicle for John Travolta? (6)
I believe the answer is:
grease
'lubricate' is the definition.
(synonyms)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for grease that I've seen before include "Thick lubricant or frying oil" , "Musical starring John Travolta and Olivia Newton-John" , "Possible cause of slip-up" , "Rock musical" , "Lubricate - musical" .)