Always ten really confused (9)
I believe the answer is:
eternally
'always' is the definition.
(thesaurus)
'ten really confused' is the wordplay.
'confused' indicates an anagram.
'ten'+'really'='tenreally'
'tenreally' is an anagram of 'ETERNALLY'.
(Other definitions for eternally that I've seen before include "For evermore" , "Always and forever" , "for good" , "constantly" , "Nearly let out forever" .)