High-sounding holy shrouds on canvas (11)
I believe the answer is:
pretentious
'high-sounding' is the definition.
(similar in meaning)
'holy shrouds on canvas' is the wordplay.
'holy' becomes 'pious'.
'shrouds' indicates putting letters inside (shrouds can mean covers or contains).
'on' becomes 're' (regarding).
'canvas' becomes 'tent' (I've seen this in another clue).
're'+'tent'='retent'
'pious' going around 'retent' is 'PRETENTIOUS'.
(Other definitions for pretentious that I've seen before include "Arrogant" , "Affected" , "Pompous, self-important" , "trying to impress" , "Foolishly grandiose" .)