Postpone aeroplane yarn?
I believe the answer is:
mothball
This clue might be a double definition.
'postpone' is the first definition.
Although both the answer and definition are verbs in their base form, I don't see how they can define each other.
'aeroplane yarn?' is the second definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps there's an association between them I don't understand?
Can you help me to learn more?
(Other definitions for mothball that I've seen before include "Naphthalene or camphor sphere" , "put on back burner" , "Put into long-term storage" , "Camphor sphere used to keep stored clothing in good condition" , "Put on ice" .)