What is the best shopping area closest to HK airport? We will be on stopover for 10 hours only.

I think the Citygate in Tung Chung is suggested and you can take airport shuttle bus line S1 can take you to reach directly.
To be honest, ten hours are enough for you to visit the Central area in HK Island. The airport express can take you to reach HK Station in about 24 minutes. Then you can walk to reach Central area for shopping. After shopping, you can take it back to the airport easily and fast.

Thanks