Conscious of feature missing in tea set (5)
I believe the answer is:
aware
'conscious of' is the definition.
(thesaurus)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for aware that I've seen before include "Apprised or informed" , "Informed; conscious" , "Acquainted with or mindful of" , "Acquainted with or conscious of" , "Alert, conscious of" .)