Clear about covering except missing ten, and a container (10)
I believe the answer is:
receptacle
'container' is the definition.
(receptacle is a kind of container)
'clear about covering except missing ten and a' is the wordplay.
'clear about' becomes 'rcle' (I can't justify this - if you can you should believe this answer much more).
'covering' means one lot of letters goes inside another.
'missing' indicates named letters should be taken away.
'ten' becomes 'x' (roman numeral).
'and' means one lot of letters go next to another.
'except' with 'x' removed is 'ecept'.
'ecept'+'a'='ecepta'
'rcle' enclosing 'ecepta' is 'RECEPTACLE'.
Can you help me to learn more?
(Other definitions for receptacle that I've seen before include "tank, say" , "Object made to contain something" , "bin, perhaps" , "Container" , "What may contain something" .)