The opposite of a sun bonnet? (3,3)
'sun bonnet?' is the definition.
The answer and definition can be both natural objects as well as being singular nouns.
Maybe there's an association between them I don't understand?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for icecap that I've seen before include "what's on mountain peak?" , "Permanent coating of white on a mountain-top" , "frozen peak" , "mass covering the top of Everest?" , "Frozen topping" .)
I'm afraid I can't explain this answer.
Can you help me to learn more?
(Other definitions for ice cap that I've seen before include "Permanent frozen polar cover" , "polar area" , "Polar feature" , "one providing cover for Pole" , "Cold mass permanently covering the polar regions or mountain peaks" .)