Psychiatrist's artist companion describing limits of outdoor school (9)
I believe the answer is:
rorschach
'psychiatrist's' is the definition.
(I've seen this before)
'artist companion describing limits of outdoor school' is the wordplay.
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'companion' becomes 'ch' (Companion of Honour).
'describing' is an insertion indicator (describe can mean to form the outline of).
'limits of' suggests removing the centre.
'school' becomes 'sch' (common abbreviation).
'outdoor' with its centre taken out is 'or'.
'ra'+'ch'='rach'
'or'+'sch'='orsch'
'rach' going around 'orsch' is 'RORSCHACH'.
(Other definitions for rorschach that I've seen before include "test creator" , "Psychiatrist" .)