Trustworthy theatre board accommodating Feydeau's last (9)
I believe the answer is:
reputable
'trustworthy' is the definition.
(thesaurus)
'theatre board accommodating feydeau's last' is the wordplay.
'theatre' becomes 'rep' (I've seen this in other clues).
'board' becomes 'table' ('table' can be a synonym of 'board').
'accommodating' means one lot of letters goes inside another.
'last' suggests the final letters.
The last letter of 'feydeau' is 'u'.
'rep'+'table'='reptable'
'reptable' enclosing 'u' is 'REPUTABLE'.
(Other definitions for reputable that I've seen before include "Well-regarded" , "Well thought of" , "of good name" , "Trustworthy" , "Upright" .)