Educational institution choosy dons clear out (9,6)
I believe the answer is:
secondary school
'educational institution' is the definition.
(I know that secondary school is a type of school)
'choosy dons clear out' is the wordplay.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'choosy'+'dons'+'clear'='choosydonsclear'
'choosydonsclear' with letters rearranged gives 'SECONDARY SCHOOL'.
(Other definitions for secondary school that I've seen before include "Where youth's instructed" , "Educational establishment" .)