Burdened saint put on a glower (7)
I believe the answer is:
saddled
'burdened' is the definition.
('saddle' can be a synonym of 'burden')
'saint put on a glower' is the wordplay.
'saint' becomes 's'.
'put on' becomes 'add' (as in adding something on).
'a glower' becomes 'led' (I've seen this in other clues).
's'+'add'+'led'='SADDLED'
(Other definitions for saddled that I've seen before include "Horse might be" , "Ready to ride" , "stuck" , "Burdened with" , "Encumbered" .)